Gecko [ fernandoquevedodop.com ]

Name	Size	Permission
2to3.html	70.96 KB	-rw-r--r--
__future__.html	20.75 KB	-rw-r--r--
__main__.html	44.87 KB	-rw-r--r--
_thread.html	30.39 KB	-rw-r--r--
abc.html	46.87 KB	-rw-r--r--
aifc.html	35.56 KB	-rw-r--r--
allos.html	34.33 KB	-rw-r--r--
archiving.html	17 KB	-rw-r--r--
argparse.html	300.89 KB	-rw-r--r--
array.html	37.28 KB	-rw-r--r--
ast.html	293.08 KB	-rw-r--r--
asynchat.html	37.41 KB	-rw-r--r--
asyncio-api-index.html	27.68 KB	-rw-r--r--
asyncio-dev.html	36.1 KB	-rw-r--r--
asyncio-eventloop.html	204.43 KB	-rw-r--r--
asyncio-exceptions.html	17.11 KB	-rw-r--r--
asyncio-future.html	38.23 KB	-rw-r--r--
asyncio-llapi-index.html	61.97 KB	-rw-r--r--
asyncio-platforms.html	21.77 KB	-rw-r--r--
asyncio-policy.html	39.56 KB	-rw-r--r--
asyncio-protocol.html	118.33 KB	-rw-r--r--
asyncio-queue.html	31.86 KB	-rw-r--r--
asyncio-stream.html	69.98 KB	-rw-r--r--
asyncio-subprocess.html	49.25 KB	-rw-r--r--
asyncio-sync.html	42.79 KB	-rw-r--r--
asyncio-task.html	109.14 KB	-rw-r--r--
asyncio.html	17.31 KB	-rw-r--r--
asyncore.html	49.36 KB	-rw-r--r--
atexit.html	22.87 KB	-rw-r--r--
audioop.html	46 KB	-rw-r--r--
audit_events.html	72.85 KB	-rw-r--r--
base64.html	48.09 KB	-rw-r--r--
bdb.html	66 KB	-rw-r--r--
binary.html	15.97 KB	-rw-r--r--
binascii.html	36.3 KB	-rw-r--r--
binhex.html	15.97 KB	-rw-r--r--
bisect.html	43.38 KB	-rw-r--r--
builtins.html	14.87 KB	-rw-r--r--
bz2.html	50.68 KB	-rw-r--r--
calendar.html	69.35 KB	-rw-r--r--
cgi.html	59.95 KB	-rw-r--r--
cgitb.html	19.96 KB	-rw-r--r--
chunk.html	22.21 KB	-rw-r--r--
cmath.html	43.89 KB	-rw-r--r--
cmd.html	50.42 KB	-rw-r--r--
code.html	35.38 KB	-rw-r--r--
codecs.html	157.96 KB	-rw-r--r--
codeop.html	18.26 KB	-rw-r--r--
collections.abc.html	79.17 KB	-rw-r--r--
collections.html	189.43 KB	-rw-r--r--
colorsys.html	17.31 KB	-rw-r--r--
compileall.html	50.68 KB	-rw-r--r--
concurrency.html	24.15 KB	-rw-r--r--
concurrent.futures.html	79.03 KB	-rw-r--r--
concurrent.html	11.56 KB	-rw-r--r--
configparser.html	159.4 KB	-rw-r--r--
constants.html	22.41 KB	-rw-r--r--
contextlib.html	117.2 KB	-rw-r--r--
contextvars.html	38.38 KB	-rw-r--r--
copy.html	17.92 KB	-rw-r--r--
copyreg.html	18.63 KB	-rw-r--r--
crypt.html	28.29 KB	-rw-r--r--
crypto.html	13.93 KB	-rw-r--r--
csv.html	82.89 KB	-rw-r--r--
ctypes.html	295.49 KB	-rw-r--r--
curses.ascii.html	32.04 KB	-rw-r--r--
curses.html	221.24 KB	-rw-r--r--
curses.panel.html	22.16 KB	-rw-r--r--
custominterp.html	11.85 KB	-rw-r--r--
dataclasses.html	113.16 KB	-rw-r--r--
datatypes.html	31.82 KB	-rw-r--r--
datetime.html	374.92 KB	-rw-r--r--
dbm.html	51.16 KB	-rw-r--r--
debug.html	17 KB	-rw-r--r--
decimal.html	270.12 KB	-rw-r--r--
development.html	32.34 KB	-rw-r--r--
devmode.html	31.72 KB	-rw-r--r--
dialog.html	43.03 KB	-rw-r--r--
difflib.html	111.99 KB	-rw-r--r--
dis.html	136.07 KB	-rw-r--r--
distribution.html	13.67 KB	-rw-r--r--
distutils.html	14.73 KB	-rw-r--r--
doctest.html	199.32 KB	-rw-r--r--
email.charset.html	31.92 KB	-rw-r--r--
email.compat32-message.html	97.74 KB	-rw-r--r--
email.contentmanager.html	37.02 KB	-rw-r--r--
email.encoders.html	18.47 KB	-rw-r--r--
email.errors.html	24.45 KB	-rw-r--r--
email.examples.html	60.49 KB	-rw-r--r--
email.generator.html	48.79 KB	-rw-r--r--
email.header.html	37.61 KB	-rw-r--r--
email.headerregistry.html	66.26 KB	-rw-r--r--
email.html	30.75 KB	-rw-r--r--
email.iterators.html	18.23 KB	-rw-r--r--
email.message.html	99.75 KB	-rw-r--r--
email.mime.html	44.89 KB	-rw-r--r--
email.parser.html	57.39 KB	-rw-r--r--
email.policy.html	84.24 KB	-rw-r--r--
email.utils.html	42.57 KB	-rw-r--r--
ensurepip.html	23.9 KB	-rw-r--r--
enum.html	151 KB	-rw-r--r--
errno.html	60.17 KB	-rw-r--r--
exceptions.html	108.44 KB	-rw-r--r--
faulthandler.html	31.5 KB	-rw-r--r--
fcntl.html	36.67 KB	-rw-r--r--
filecmp.html	32.08 KB	-rw-r--r--
fileformats.html	13.52 KB	-rw-r--r--
fileinput.html	40.37 KB	-rw-r--r--
filesys.html	16.78 KB	-rw-r--r--
fnmatch.html	21.02 KB	-rw-r--r--
fractions.html	35.29 KB	-rw-r--r--
frameworks.html	16.15 KB	-rw-r--r--
ftplib.html	71.97 KB	-rw-r--r--
functional.html	12.19 KB	-rw-r--r--
functions.html	260.33 KB	-rw-r--r--
functools.html	92.96 KB	-rw-r--r--
gc.html	40.97 KB	-rw-r--r--
getopt.html	29.4 KB	-rw-r--r--
getpass.html	16.01 KB	-rw-r--r--
gettext.html	98.02 KB	-rw-r--r--
glob.html	27.2 KB	-rw-r--r--
graphlib.html	34.82 KB	-rw-r--r--
grp.html	16.03 KB	-rw-r--r--
gzip.html	45.65 KB	-rw-r--r--
hashlib.html	93.19 KB	-rw-r--r--
heapq.html	42.43 KB	-rw-r--r--
hmac.html	24.74 KB	-rw-r--r--
html.entities.html	14.91 KB	-rw-r--r--
html.html	14.81 KB	-rw-r--r--
html.parser.html	47.7 KB	-rw-r--r--
http.client.html	85.63 KB	-rw-r--r--
http.cookiejar.html	113.94 KB	-rw-r--r--
http.cookies.html	47.64 KB	-rw-r--r--
http.html	45.52 KB	-rw-r--r--
http.server.html	73.05 KB	-rw-r--r--
i18n.html	13.44 KB	-rw-r--r--
idle.html	77.18 KB	-rw-r--r--
imaplib.html	87.08 KB	-rw-r--r--
imghdr.html	17.94 KB	-rw-r--r--
imp.html	54.32 KB	-rw-r--r--
importlib.html	239.96 KB	-rw-r--r--
importlib.metadata.html	43.14 KB	-rw-r--r--
index.html	75.06 KB	-rw-r--r--
inspect.html	168.74 KB	-rw-r--r--
internet.html	29.89 KB	-rw-r--r--
intro.html	13.81 KB	-rw-r--r--
io.html	154.15 KB	-rw-r--r--
ipaddress.html	137.75 KB	-rw-r--r--
ipc.html	12.6 KB	-rw-r--r--
itertools.html	153.27 KB	-rw-r--r--
json.html	98.9 KB	-rw-r--r--
keyword.html	14.88 KB	-rw-r--r--
language.html	16.71 KB	-rw-r--r--
linecache.html	18.09 KB	-rw-r--r--
locale.html	77.35 KB	-rw-r--r--
logging.config.html	100.3 KB	-rw-r--r--
logging.handlers.html	146.28 KB	-rw-r--r--
logging.html	169.67 KB	-rw-r--r--
lzma.html	66.89 KB	-rw-r--r--
mailbox.html	176.34 KB	-rw-r--r--
mailcap.html	20.86 KB	-rw-r--r--
markup.html	22.31 KB	-rw-r--r--
marshal.html	24.43 KB	-rw-r--r--
math.html	85.82 KB	-rw-r--r--
mimetypes.html	40.27 KB	-rw-r--r--
mm.html	11.16 KB	-rw-r--r--
mmap.html	55.53 KB	-rw-r--r--
modulefinder.html	23.67 KB	-rw-r--r--
modules.html	15.88 KB	-rw-r--r--
msilib.html	78.38 KB	-rw-r--r--
msvcrt.html	29.22 KB	-rw-r--r--
multiprocessing.html	405.24 KB	-rw-r--r--
multiprocessing.shared_memory....	60 KB	-rw-r--r--
netdata.html	20.24 KB	-rw-r--r--
netrc.html	20.39 KB	-rw-r--r--
nis.html	16.76 KB	-rw-r--r--
nntplib.html	84.93 KB	-rw-r--r--
numbers.html	45.67 KB	-rw-r--r--
numeric.html	19.29 KB	-rw-r--r--
operator.html	107.32 KB	-rw-r--r--
optparse.html	256.96 KB	-rw-r--r--
os.html	594.39 KB	-rw-r--r--
os.path.html	65.54 KB	-rw-r--r--
ossaudiodev.html	56.35 KB	-rw-r--r--
pathlib.html	170.01 KB	-rw-r--r--
pdb.html	68.67 KB	-rw-r--r--
persistence.html	19.13 KB	-rw-r--r--
pickle.html	154.45 KB	-rw-r--r--
pickletools.html	22.92 KB	-rw-r--r--
pipes.html	21.7 KB	-rw-r--r--
pkgutil.html	42.76 KB	-rw-r--r--
platform.html	45.08 KB	-rw-r--r--
plistlib.html	30.06 KB	-rw-r--r--
poplib.html	41.42 KB	-rw-r--r--
posix.html	20.96 KB	-rw-r--r--
pprint.html	55.35 KB	-rw-r--r--
profile.html	84.63 KB	-rw-r--r--
pty.html	23.7 KB	-rw-r--r--
pwd.html	16.84 KB	-rw-r--r--
py_compile.html	29 KB	-rw-r--r--
pyclbr.html	24.06 KB	-rw-r--r--
pydoc.html	19.59 KB	-rw-r--r--
pyexpat.html	104.38 KB	-rw-r--r--
python.html	22.46 KB	-rw-r--r--
queue.html	43.39 KB	-rw-r--r--
quopri.html	18.64 KB	-rw-r--r--
random.html	86.31 KB	-rw-r--r--
re.html	214.24 KB	-rw-r--r--
readline.html	50.19 KB	-rw-r--r--
reprlib.html	30.85 KB	-rw-r--r--
resource.html	48.26 KB	-rw-r--r--
rlcompleter.html	18.06 KB	-rw-r--r--
runpy.html	30.99 KB	-rw-r--r--
sched.html	27.04 KB	-rw-r--r--
secrets.html	30.2 KB	-rw-r--r--
security_warnings.html	16.21 KB	-rw-r--r--
select.html	74.58 KB	-rw-r--r--
selectors.html	41.91 KB	-rw-r--r--
shelve.html	36.54 KB	-rw-r--r--
shlex.html	61.03 KB	-rw-r--r--
shutil.html	100.13 KB	-rw-r--r--
signal.html	95.39 KB	-rw-r--r--
site.html	38.16 KB	-rw-r--r--
smtpd.html	44.09 KB	-rw-r--r--
smtplib.html	81.4 KB	-rw-r--r--
sndhdr.html	16.4 KB	-rw-r--r--
socket.html	256.95 KB	-rw-r--r--
socketserver.html	91.95 KB	-rw-r--r--
spwd.html	16.71 KB	-rw-r--r--
sqlite3.html	225.51 KB	-rw-r--r--
ssl.html	328.83 KB	-rw-r--r--
stat.html	57.79 KB	-rw-r--r--
statistics.html	123.22 KB	-rw-r--r--
stdtypes.html	615.43 KB	-rw-r--r--
string.html	108.03 KB	-rw-r--r--
stringprep.html	24.94 KB	-rw-r--r--
struct.html	70.58 KB	-rw-r--r--
subprocess.html	199.03 KB	-rw-r--r--
sunau.html	39.84 KB	-rw-r--r--
superseded.html	26.21 KB	-rw-r--r--
symtable.html	33.26 KB	-rw-r--r--
sys.html	198.83 KB	-rw-r--r--
sysconfig.html	39.81 KB	-rw-r--r--
syslog.html	27.36 KB	-rw-r--r--
tabnanny.html	16.18 KB	-rw-r--r--
tarfile.html	161.92 KB	-rw-r--r--
telnetlib.html	38.21 KB	-rw-r--r--
tempfile.html	58.39 KB	-rw-r--r--
termios.html	22.86 KB	-rw-r--r--
test.html	222.85 KB	-rw-r--r--
text.html	16.8 KB	-rw-r--r--
textwrap.html	48.83 KB	-rw-r--r--
threading.html	128.33 KB	-rw-r--r--
time.html	107.46 KB	-rw-r--r--
timeit.html	52.63 KB	-rw-r--r--
tk.html	28.08 KB	-rw-r--r--
tkinter.colorchooser.html	14.49 KB	-rw-r--r--
tkinter.dnd.html	17.09 KB	-rw-r--r--
tkinter.font.html	22.21 KB	-rw-r--r--
tkinter.html	106.85 KB	-rw-r--r--
tkinter.messagebox.html	20.09 KB	-rw-r--r--
tkinter.scrolledtext.html	14.52 KB	-rw-r--r--
tkinter.tix.html	59.69 KB	-rw-r--r--
tkinter.ttk.html	138.37 KB	-rw-r--r--
token.html	45.73 KB	-rw-r--r--
tokenize.html	39.86 KB	-rw-r--r--
trace.html	38.85 KB	-rw-r--r--
traceback.html	75.61 KB	-rw-r--r--
tracemalloc.html	122.33 KB	-rw-r--r--
tty.html	14.46 KB	-rw-r--r--
turtle.html	271.71 KB	-rw-r--r--
types.html	64.85 KB	-rw-r--r--
typing.html	315.69 KB	-rw-r--r--
unicodedata.html	27.3 KB	-rw-r--r--
unittest.html	310.01 KB	-rw-r--r--
unittest.mock-examples.html	177.75 KB	-rw-r--r--
unittest.mock.html	363.51 KB	-rw-r--r--
unix.html	13.46 KB	-rw-r--r--
urllib.error.html	18.56 KB	-rw-r--r--
urllib.html	12.92 KB	-rw-r--r--
urllib.parse.html	104.65 KB	-rw-r--r--
urllib.request.html	208.87 KB	-rw-r--r--
urllib.robotparser.html	22.63 KB	-rw-r--r--
uu.html	18.2 KB	-rw-r--r--
uuid.html	42.88 KB	-rw-r--r--
venv.html	90.43 KB	-rw-r--r--
warnings.html	69.13 KB	-rw-r--r--
wave.html	36.12 KB	-rw-r--r--
weakref.html	73.36 KB	-rw-r--r--
webbrowser.html	33.98 KB	-rw-r--r--
windows.html	12.32 KB	-rw-r--r--
winreg.html	89.48 KB	-rw-r--r--
winsound.html	26.3 KB	-rw-r--r--
wsgiref.html	111.52 KB	-rw-r--r--
xdrlib.html	42.07 KB	-rw-r--r--
xml.dom.html	114.66 KB	-rw-r--r--
xml.dom.minidom.html	49.6 KB	-rw-r--r--
xml.dom.pulldom.html	30.06 KB	-rw-r--r--
xml.etree.elementtree.html	186.49 KB	-rw-r--r--
xml.html	22.34 KB	-rw-r--r--
xml.sax.handler.html	55.78 KB	-rw-r--r--
xml.sax.html	31.74 KB	-rw-r--r--
xml.sax.reader.html	56.23 KB	-rw-r--r--
xml.sax.utils.html	22.28 KB	-rw-r--r--
xmlrpc.client.html	79.73 KB	-rw-r--r--
xmlrpc.html	11.9 KB	-rw-r--r--
xmlrpc.server.html	63.56 KB	-rw-r--r--
zipapp.html	52.45 KB	-rw-r--r--
zipfile.html	116.59 KB	-rw-r--r--
zipimport.html	33.76 KB	-rw-r--r--
zlib.html	42.29 KB	-rw-r--r--
zoneinfo.html	57.25 KB	-rw-r--r--

Code Editor : abc.html

<!DOCTYPE html>

<title>abc — Abstract Base Classes &#8212; Python 3.10.12 documentation</title><meta name="viewport" content="width=device-width, initial-scale=1.0">
 
 <link rel="stylesheet" type="text/css" href="../_static/pygments.css" />
 <link rel="stylesheet" type="text/css" href="../_static/pydoctheme.css?2022.1" />
 
 <script data-url_root="../" id="documentation_options" src="../_static/documentation_options.js"></script>
 <script src="../_static/jquery.js"></script>
 <script src="../_static/underscore.js"></script>
 <script src="../_static/doctools.js"></script>
 
 <script src="../_static/sidebar.js"></script>
 
 <link rel="search" type="application/opensearchdescription+xml"
 title="Search within Python 3.10.12 documentation"
 href="../_static/opensearch.xml"/>
 <link rel="author" title="About these documents" href="../about.html" />
 <link rel="index" title="Index" href="../genindex.html" />
 <link rel="search" title="Search" href="../search.html" />
 <link rel="copyright" title="Copyright" href="../copyright.html" />
 <link rel="next" title="atexit — Exit handlers" href="atexit.html" />
 <link rel="prev" title="contextlib — Utilities for with-statement contexts" href="contextlib.html" />
 <link rel="canonical" href="file:///usr/share/doc/python3.10/html/library/abc.html" />

</head>
<body>
<div class="mobile-nav">
 <input type="checkbox" id="menuToggler" class="toggler__input" aria-controls="navigation"
 aria-pressed="false" aria-expanded="false" role="button" aria-label="Menu" />
 <label for="menuToggler" class="toggler__label">
 
 </label>
 <nav class="nav-content" role="navigation">
 <a href="https://www.python.org/" class="nav-logo">
 <img src="../_static/py.svg" alt="Logo"/>
 </a>
 <div class="version_switcher_placeholder"></div>
 <form role="search" class="search" action="../search.html" method="get">
 <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" class="search-icon">
 <path fill-rule="nonzero"
 d="M15.5 14h-.79l-.28-.27a6.5 6.5 0 001.48-5.34c-.47-2.78-2.79-5-5.59-5.34a6.505 6.505 0 00-7.27 7.27c.34 2.8 2.56 5.12 5.34 5.59a6.5 6.5 0 005.34-1.48l.27.28v.79l4.25 4.25c.41.41 1.08.41 1.49 0 .41-.41.41-1.08 0-1.49L15.5 14zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z" fill="#444"></path>
 </svg>
 <input type="text" name="q" aria-label="Quick search"/>
 <input type="submit" value="Go"/>
 </form>
 </nav>
 <div class="menu-wrapper">
 <nav class="menu" role="navigation" aria-label="main navigation">
 <div class="language_switcher_placeholder"></div>
 <h4>Previous topic</h4>
 <a href="contextlib.html"
 title="previous chapter"><code class="xref py py-mod docutils literal notranslate">contextlib</code> — Utilities for <code class="xref std std-keyword docutils literal notranslate">with</code>-statement contexts</a>
 <h4>Next topic</h4>
 <a href="atexit.html"
 title="next chapter"><code class="xref py py-mod docutils literal notranslate">atexit</code> — Exit handlers</a>
 <div role="note" aria-label="source link">
 <h3>This Page</h3>
 <ul class="this-page-menu">
 <li><a href="../bugs.html">Report a Bug</a></li>
 <li>
 <a href="https://github.com/python/cpython/blob/3.10/Doc/library/abc.rst"
 rel="nofollow">Show Source
 </a>
 </li>
 </ul>
 </div>
 </nav>
 </div>
</div>

<div class="related" role="navigation" aria-label="related navigation">
 <h3>Navigation</h3>
 <ul>
 <li class="right" style="margin-right: 10px">
 <a href="../genindex.html" title="General Index"
 accesskey="I">index</a></li>
 <li class="right" >
 <a href="../py-modindex.html" title="Python Module Index"
 >modules</a> |</li>
 <li class="right" >
 <a href="atexit.html" title="atexit — Exit handlers"
 accesskey="N">next</a> |</li>
 <li class="right" >
 <a href="contextlib.html" title="contextlib — Utilities for with-statement contexts"
 accesskey="P">previous</a> |</li>

<li><img src="../_static/py.svg" alt="python logo" style="vertical-align: middle; margin-top: -1px"/></li>
 <li><a href="https://www.python.org/">Python</a> &#187;</li>
 <li class="switchers">
 <div class="language_switcher_placeholder"></div>
 <div class="version_switcher_placeholder"></div>
 </li>
 <li>
 
 </li>
 <li id="cpython-language-and-version">
 <a href="../index.html">3.10.12 Documentation</a> &#187;
 </li>

<li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
 <li class="nav-item nav-item-2"><a href="python.html" accesskey="U">Python Runtime Services</a> &#187;</li>
 <li class="nav-item nav-item-this"><a href=""><code class="xref py py-mod docutils literal notranslate">abc</code> — Abstract Base Classes</a></li>
 <li class="right">

<div class="document">
 <div class="documentwrapper">
 <div class="bodywrapper">
 <div class="body" role="main">
 
 <section id="module-abc">
<h1><a class="reference internal" href="#module-abc" title="abc: Abstract base classes according to :pep:`3119`."><code class="xref py py-mod docutils literal notranslate">abc</code></a> — Abstract Base Classes<a class="headerlink" href="#module-abc" title="Permalink to this headline">¶</a></h1>
Source code: <a class="reference external" href="https://github.com/python/cpython/tree/3.10/Lib/abc.py">Lib/abc.py</a>
<hr class="docutils" />
This module provides the infrastructure for defining <a class="reference internal" href="../glossary.html#term-abstract-base-class">abstract base
classes</a> (ABCs) in Python, as outlined in <a class="pep reference external" href="https://www.python.org/dev/peps/pep-3119">PEP 3119</a>;
see the PEP for why this was added to Python. (See also <a class="pep reference external" href="https://www.python.org/dev/peps/pep-3141">PEP 3141</a> and the
<a class="reference internal" href="numbers.html#module-numbers" title="numbers: Numeric abstract base classes (Complex, Real, Integral, etc.)."><code class="xref py py-mod docutils literal notranslate">numbers</code></a> module regarding a type hierarchy for numbers based on ABCs.)
The <a class="reference internal" href="collections.html#module-collections" title="collections: Container datatypes"><code class="xref py py-mod docutils literal notranslate">collections</code></a> module has some concrete classes that derive from
ABCs; these can, of course, be further derived. In addition, the
<a class="reference internal" href="collections.abc.html#module-collections.abc" title="collections.abc: Abstract base classes for containers"><code class="xref py py-mod docutils literal notranslate">collections.abc</code></a> submodule has some ABCs that can be used to test whether
a class or instance provides a particular interface, for example, if it is
<a class="reference internal" href="../glossary.html#term-hashable">hashable</a> or if it is a mapping.
This module provides the metaclass <a class="reference internal" href="#abc.ABCMeta" title="abc.ABCMeta"><code class="xref py py-class docutils literal notranslate">ABCMeta</code></a> for defining ABCs and
a helper class <a class="reference internal" href="#abc.ABC" title="abc.ABC"><code class="xref py py-class docutils literal notranslate">ABC</code></a> to alternatively define ABCs through inheritance:
<dl class="py class">
<dt class="sig sig-object py" id="abc.ABC">
class abc.ABC<a class="headerlink" href="#abc.ABC" title="Permalink to this definition">¶</a></dt>
<dd>A helper class that has <a class="reference internal" href="#abc.ABCMeta" title="abc.ABCMeta"><code class="xref py py-class docutils literal notranslate">ABCMeta</code></a> as its metaclass. With this class,
an abstract base class can be created by simply deriving from <a class="reference internal" href="#abc.ABC" title="abc.ABC"><code class="xref py py-class docutils literal notranslate">ABC</code></a>
avoiding sometimes confusing metaclass usage, for example:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>from abc import ABC

class MyABC(ABC):
 pass
</pre></div>
</div>
Note that the type of <a class="reference internal" href="#abc.ABC" title="abc.ABC"><code class="xref py py-class docutils literal notranslate">ABC</code></a> is still <a class="reference internal" href="#abc.ABCMeta" title="abc.ABCMeta"><code class="xref py py-class docutils literal notranslate">ABCMeta</code></a>, therefore
inheriting from <a class="reference internal" href="#abc.ABC" title="abc.ABC"><code class="xref py py-class docutils literal notranslate">ABC</code></a> requires the usual precautions regarding
metaclass usage, as multiple inheritance may lead to metaclass conflicts.
One may also define an abstract base class by passing the metaclass
keyword and using <a class="reference internal" href="#abc.ABCMeta" title="abc.ABCMeta"><code class="xref py py-class docutils literal notranslate">ABCMeta</code></a> directly, for example:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>from abc import ABCMeta

class MyABC(metaclass=ABCMeta):
 pass
</pre></div>
</div>
<div class="versionadded">
New in version 3.4.
</div>
</dd></dl>

<dl class="py class">
<dt class="sig sig-object py" id="abc.ABCMeta">
class abc.ABCMeta<a class="headerlink" href="#abc.ABCMeta" title="Permalink to this definition">¶</a></dt>
<dd>Metaclass for defining Abstract Base Classes (ABCs).
Use this metaclass to create an ABC. An ABC can be subclassed directly, and
then acts as a mix-in class. You can also register unrelated concrete
classes (even built-in classes) and unrelated ABCs as “virtual subclasses” –
these and their descendants will be considered subclasses of the registering
ABC by the built-in <a class="reference internal" href="functions.html#issubclass" title="issubclass"><code class="xref py py-func docutils literal notranslate">issubclass()</code></a> function, but the registering ABC
won’t show up in their MRO (Method Resolution Order) nor will method
implementations defined by the registering ABC be callable (not even via
<a class="reference internal" href="functions.html#super" title="super"><code class="xref py py-func docutils literal notranslate">super()</code></a>). <a class="footnote-reference brackets" href="#id2" id="id1">1</a>
Classes created with a metaclass of <a class="reference internal" href="#abc.ABCMeta" title="abc.ABCMeta"><code class="xref py py-class docutils literal notranslate">ABCMeta</code></a> have the following method:
<dl class="py method">
<dt class="sig sig-object py" id="abc.ABCMeta.register">
register(subclass)<a class="headerlink" href="#abc.ABCMeta.register" title="Permalink to this definition">¶</a></dt>
<dd>Register subclass as a “virtual subclass” of this ABC. For
example:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>from abc import ABC

class MyABC(ABC):
 pass

MyABC.register(tuple)

assert issubclass(tuple, MyABC)
assert isinstance((), MyABC)
</pre></div>
</div>
<div class="versionchanged">
Changed in version 3.3: Returns the registered subclass, to allow usage as a class decorator.
</div>
<div class="versionchanged">
Changed in version 3.4: To detect calls to <a class="reference internal" href="#abc.ABCMeta.register" title="abc.ABCMeta.register"><code class="xref py py-meth docutils literal notranslate">register()</code></a>, you can use the
<a class="reference internal" href="#abc.get_cache_token" title="abc.get_cache_token"><code class="xref py py-func docutils literal notranslate">get_cache_token()</code></a> function.
</div>
</dd></dl>

You can also override this method in an abstract base class:
<dl class="py method">
<dt class="sig sig-object py" id="abc.ABCMeta.__subclasshook__">
__subclasshook__(subclass)<a class="headerlink" href="#abc.ABCMeta.__subclasshook__" title="Permalink to this definition">¶</a></dt>
<dd>(Must be defined as a class method.)
Check whether subclass is considered a subclass of this ABC. This means
that you can customize the behavior of <code class="docutils literal notranslate">issubclass</code> further without the
need to call <a class="reference internal" href="#abc.ABCMeta.register" title="abc.ABCMeta.register"><code class="xref py py-meth docutils literal notranslate">register()</code></a> on every class you want to consider a
subclass of the ABC. (This class method is called from the
<code class="xref py py-meth docutils literal notranslate">__subclasscheck__()</code> method of the ABC.)
This method should return <code class="docutils literal notranslate">True</code>, <code class="docutils literal notranslate">False</code> or <code class="docutils literal notranslate">NotImplemented</code>. If
it returns <code class="docutils literal notranslate">True</code>, the subclass is considered a subclass of this ABC.
If it returns <code class="docutils literal notranslate">False</code>, the subclass is not considered a subclass of
this ABC, even if it would normally be one. If it returns
<code class="docutils literal notranslate">NotImplemented</code>, the subclass check is continued with the usual
mechanism.
</dd></dl>

For a demonstration of these concepts, look at this example ABC definition:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>class Foo:
 def __getitem__(self, index):
 ...
 def __len__(self):
 ...
 def get_iterator(self):
 return iter(self)

class MyIterable(ABC):

@abstractmethod
 def __iter__(self):
 while False:
 yield None

def get_iterator(self):
 return self.__iter__()

@classmethod
 def __subclasshook__(cls, C):
 if cls is MyIterable:
 if any(&quot;__iter__&quot; in B.__dict__ for B in C.__mro__):
 return True
 return NotImplemented

MyIterable.register(Foo)
</pre></div>
</div>
The ABC <code class="docutils literal notranslate">MyIterable</code> defines the standard iterable method,
<a class="reference internal" href="stdtypes.html#iterator.__iter__" title="iterator.__iter__"><code class="xref py py-meth docutils literal notranslate">__iter__()</code></a>, as an abstract method. The implementation given
here can still be called from subclasses. The <code class="xref py py-meth docutils literal notranslate">get_iterator()</code> method
is also part of the <code class="docutils literal notranslate">MyIterable</code> abstract base class, but it does not have
to be overridden in non-abstract derived classes.
The <a class="reference internal" href="#abc.ABCMeta.__subclasshook__" title="abc.ABCMeta.__subclasshook__"><code class="xref py py-meth docutils literal notranslate">__subclasshook__()</code></a> class method defined here says that any class
that has an <a class="reference internal" href="stdtypes.html#iterator.__iter__" title="iterator.__iter__"><code class="xref py py-meth docutils literal notranslate">__iter__()</code></a> method in its
<a class="reference internal" href="stdtypes.html#object.__dict__" title="object.__dict__"><code class="xref py py-attr docutils literal notranslate">__dict__</code></a> (or in that of one of its base classes, accessed
via the <a class="reference internal" href="stdtypes.html#class.__mro__" title="class.__mro__"><code class="xref py py-attr docutils literal notranslate">__mro__</code></a> list) is considered a <code class="docutils literal notranslate">MyIterable</code> too.
Finally, the last line makes <code class="docutils literal notranslate">Foo</code> a virtual subclass of <code class="docutils literal notranslate">MyIterable</code>,
even though it does not define an <a class="reference internal" href="stdtypes.html#iterator.__iter__" title="iterator.__iter__"><code class="xref py py-meth docutils literal notranslate">__iter__()</code></a> method (it uses
the old-style iterable protocol, defined in terms of <code class="xref py py-meth docutils literal notranslate">__len__()</code> and
<code class="xref py py-meth docutils literal notranslate">__getitem__()</code>). Note that this will not make <code class="docutils literal notranslate">get_iterator</code>
available as a method of <code class="docutils literal notranslate">Foo</code>, so it is provided separately.
</dd></dl>

The <a class="reference internal" href="#module-abc" title="abc: Abstract base classes according to :pep:`3119`."><code class="xref py py-mod docutils literal notranslate">abc</code></a> module also provides the following decorator:
<dl class="py function">
<dt class="sig sig-object py" id="abc.abstractmethod">
&#64;abc.abstractmethod<a class="headerlink" href="#abc.abstractmethod" title="Permalink to this definition">¶</a></dt>
<dd>A decorator indicating abstract methods.
Using this decorator requires that the class’s metaclass is <a class="reference internal" href="#abc.ABCMeta" title="abc.ABCMeta"><code class="xref py py-class docutils literal notranslate">ABCMeta</code></a>
or is derived from it. A class that has a metaclass derived from
<a class="reference internal" href="#abc.ABCMeta" title="abc.ABCMeta"><code class="xref py py-class docutils literal notranslate">ABCMeta</code></a> cannot be instantiated unless all of its abstract methods
and properties are overridden. The abstract methods can be called using any
of the normal ‘super’ call mechanisms. <a class="reference internal" href="#abc.abstractmethod" title="abc.abstractmethod"><code class="xref py py-func docutils literal notranslate">abstractmethod()</code></a> may be used
to declare abstract methods for properties and descriptors.
Dynamically adding abstract methods to a class, or attempting to modify the
abstraction status of a method or class once it is created, are only
supported using the <a class="reference internal" href="#abc.update_abstractmethods" title="abc.update_abstractmethods"><code class="xref py py-func docutils literal notranslate">update_abstractmethods()</code></a> function. The
<a class="reference internal" href="#abc.abstractmethod" title="abc.abstractmethod"><code class="xref py py-func docutils literal notranslate">abstractmethod()</code></a> only affects subclasses derived using regular
inheritance; “virtual subclasses” registered with the ABC’s <code class="xref py py-meth docutils literal notranslate">register()</code>
method are not affected.
When <a class="reference internal" href="#abc.abstractmethod" title="abc.abstractmethod"><code class="xref py py-func docutils literal notranslate">abstractmethod()</code></a> is applied in combination with other method
descriptors, it should be applied as the innermost decorator, as shown in
the following usage examples:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>class C(ABC):
 @abstractmethod
 def my_abstract_method(self, arg1):
 ...
 @classmethod
 @abstractmethod
 def my_abstract_classmethod(cls, arg2):
 ...
 @staticmethod
 @abstractmethod
 def my_abstract_staticmethod(arg3):
 ...

@property
 @abstractmethod
 def my_abstract_property(self):
 ...
 @my_abstract_property.setter
 @abstractmethod
 def my_abstract_property(self, val):
 ...

@abstractmethod
 def _get_x(self):
 ...
 @abstractmethod
 def _set_x(self, val):
 ...
 x = property(_get_x, _set_x)
</pre></div>
</div>
In order to correctly interoperate with the abstract base class machinery,
the descriptor must identify itself as abstract using
<code class="xref py py-attr docutils literal notranslate">__isabstractmethod__</code>. In general, this attribute should be <code class="docutils literal notranslate">True</code>
if any of the methods used to compose the descriptor are abstract. For
example, Python’s built-in <a class="reference internal" href="functions.html#property" title="property"><code class="xref py py-class docutils literal notranslate">property</code></a> does the equivalent of:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>class Descriptor:
 ...
 @property
 def __isabstractmethod__(self):
 return any(getattr(f, &#39;__isabstractmethod__&#39;, False) for
 f in (self._fget, self._fset, self._fdel))
</pre></div>
</div>
<div class="admonition note">
Note
Unlike Java abstract methods, these abstract
methods may have an implementation. This implementation can be
called via the <a class="reference internal" href="functions.html#super" title="super"><code class="xref py py-func docutils literal notranslate">super()</code></a> mechanism from the class that
overrides it. This could be useful as an end-point for a
super-call in a framework that uses cooperative
multiple-inheritance.
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="abc.abstractstaticmethod">
&#64;abc.abstractstaticmethod<a class="headerlink" href="#abc.abstractstaticmethod" title="Permalink to this definition">¶</a></dt>
<dd><div class="versionadded">
New in version 3.2.
</div>
<div class="deprecated">
Deprecated since version 3.3: It is now possible to use <a class="reference internal" href="functions.html#staticmethod" title="staticmethod"><code class="xref py py-class docutils literal notranslate">staticmethod</code></a> with
<a class="reference internal" href="#abc.abstractmethod" title="abc.abstractmethod"><code class="xref py py-func docutils literal notranslate">abstractmethod()</code></a>, making this decorator redundant.
</div>
A subclass of the built-in <a class="reference internal" href="functions.html#staticmethod" title="staticmethod"><code class="xref py py-func docutils literal notranslate">staticmethod()</code></a>, indicating an abstract
staticmethod. Otherwise it is similar to <a class="reference internal" href="#abc.abstractmethod" title="abc.abstractmethod"><code class="xref py py-func docutils literal notranslate">abstractmethod()</code></a>.
This special case is deprecated, as the <a class="reference internal" href="functions.html#staticmethod" title="staticmethod"><code class="xref py py-func docutils literal notranslate">staticmethod()</code></a> decorator
is now correctly identified as abstract when applied to an abstract
method:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>class C(ABC):
 @staticmethod
 @abstractmethod
 def my_abstract_staticmethod(arg):
 ...
</pre></div>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="abc.abstractproperty">
&#64;abc.abstractproperty<a class="headerlink" href="#abc.abstractproperty" title="Permalink to this definition">¶</a></dt>
<dd><div class="deprecated">
Deprecated since version 3.3: It is now possible to use <a class="reference internal" href="functions.html#property" title="property"><code class="xref py py-class docutils literal notranslate">property</code></a>, <code class="xref py py-meth docutils literal notranslate">property.getter()</code>,
<code class="xref py py-meth docutils literal notranslate">property.setter()</code> and <code class="xref py py-meth docutils literal notranslate">property.deleter()</code> with
<a class="reference internal" href="#abc.abstractmethod" title="abc.abstractmethod"><code class="xref py py-func docutils literal notranslate">abstractmethod()</code></a>, making this decorator redundant.
</div>
A subclass of the built-in <a class="reference internal" href="functions.html#property" title="property"><code class="xref py py-func docutils literal notranslate">property()</code></a>, indicating an abstract
property.
This special case is deprecated, as the <a class="reference internal" href="functions.html#property" title="property"><code class="xref py py-func docutils literal notranslate">property()</code></a> decorator
is now correctly identified as abstract when applied to an abstract
method:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>class C(ABC):
 @property
 @abstractmethod
 def my_abstract_property(self):
 ...
</pre></div>
</div>
The above example defines a read-only property; you can also define a
read-write abstract property by appropriately marking one or more of the
underlying methods as abstract:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>class C(ABC):
 @property
 def x(self):
 ...

@x.setter
 @abstractmethod
 def x(self, val):
 ...
</pre></div>
</div>
If only some components are abstract, only those components need to be
updated to create a concrete property in a subclass:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>class D(C):
 @C.x.setter
 def x(self, val):
 ...
</pre></div>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="abc.update_abstractmethods">
abc.update_abstractmethods(cls)<a class="headerlink" href="#abc.update_abstractmethods" title="Permalink to this definition">¶</a></dt>
<dd>A function to recalculate an abstract class’s abstraction status. This
function should be called if a class’s abstract methods have been
implemented or changed after it was created. Usually, this function should
be called from within a class decorator.
Returns cls, to allow usage as a class decorator.
If cls is not an instance of <a class="reference internal" href="#abc.ABCMeta" title="abc.ABCMeta"><code class="xref py py-class docutils literal notranslate">ABCMeta</code></a>, does nothing.
<div class="admonition note">
Note
This function assumes that cls’s superclasses are already updated.
It does not update any subclasses.
</div>
<div class="versionadded">
New in version 3.10.
</div>
</dd></dl>

Footnotes
<dl class="footnote brackets">
<dt class="label" id="id2"><a class="fn-backref" href="#id1">1</a></dt>
<dd>C++ programmers should note that Python’s virtual base class
concept is not the same as C++’s.
</dd>
</dl>
</section>

<div class="clearer"></div>
 </div>
 </div>
 </div>
 <div class="sphinxsidebar" role="navigation" aria-label="main navigation">
 <div class="sphinxsidebarwrapper">
 <h4>Previous topic</h4>
 <a href="contextlib.html"
 title="previous chapter"><code class="xref py py-mod docutils literal notranslate">contextlib</code> — Utilities for <code class="xref std std-keyword docutils literal notranslate">with</code>-statement contexts</a>
 <h4>Next topic</h4>
 <a href="atexit.html"
 title="next chapter"><code class="xref py py-mod docutils literal notranslate">atexit</code> — Exit handlers</a>
 <div role="note" aria-label="source link">
 <h3>This Page</h3>
 <ul class="this-page-menu">
 <li><a href="../bugs.html">Report a Bug</a></li>
 <li>
 <a href="https://github.com/python/cpython/blob/3.10/Doc/library/abc.rst"
 rel="nofollow">Show Source
 </a>
 </li>
 </ul>
 </div>
 </div>
 </div>
 <div class="clearer"></div>
 </div> 
 <div class="related" role="navigation" aria-label="related navigation">
 <h3>Navigation</h3>
 <ul>
 <li class="right" style="margin-right: 10px">
 <a href="../genindex.html" title="General Index"
 >index</a></li>
 <li class="right" >
 <a href="../py-modindex.html" title="Python Module Index"
 >modules</a> |</li>
 <li class="right" >
 <a href="atexit.html" title="atexit — Exit handlers"
 >next</a> |</li>
 <li class="right" >
 <a href="contextlib.html" title="contextlib — Utilities for with-statement contexts"
 >previous</a> |</li>

<li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
 <li class="nav-item nav-item-2"><a href="python.html" >Python Runtime Services</a> &#187;</li>
 <li class="nav-item nav-item-this"><a href=""><code class="xref py py-mod docutils literal notranslate">abc</code> — Abstract Base Classes</a></li>
 <li class="right">

<div class="inline-search" role="search">
 <form class="inline-search" action="../search.html" method="get">
 <input placeholder="Quick search" aria-label="Quick search" type="text" name="q" />
 <input type="submit" value="Go" />
 <input type="hidden" name="check_keywords" value="yes" />
 <input type="hidden" name="area" value="default" />
 </form>
 </div>
 |
 </li>
 
 </ul>
 </div> 
 <div class="footer">
 &copy; <a href="../copyright.html">Copyright</a> 2001-2026, Python Software Foundation.
 
 This page is licensed under the Python Software Foundation License Version 2.
 
 Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License.
 
 See <a href="/license.html">History and License</a> for more information.

The Python Software Foundation is a non-profit corporation.
<a href="https://www.python.org/psf/donations/">Please donate.</a>

Last updated on January 26, 2026.
 <a href="/bugs.html">Found a bug</a>?

Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 4.3.2.
 </div>

</body>
</html>

${this.title}

Code Editor : abc.html