types.TracebackType The type of traceback objects such as found in sys.exc_info()[2].

class importlib.machinery.BuiltinImporter An importer for built-in modules. All known built-in modules are listed in sys.builtin_module_names. This class implements the importlib.abc.MetaPathFinder and importlib.abc.InspectLoader ABCs. Only class methods are defined by this class to alleviate the need for instantiation. Changed in version 3.5: As part of PEP 489, the builtin importer now implements Loader.create_module() and Loader.exec_module()

doctest.DocTestSuite(module=None, globs=None, extraglobs=None, test_finder=None, setUp=None, tearDown=None, checker=None) Convert doctest tests for a module to a unittest.TestSuite. The returned unittest.TestSuite is to be run by the unittest framework and runs each doctest in the module. If any of the doctests fail, then the synthesized unit test fails, and a failureException exception is raised showing the name of the file containing the test and a (sometimes approximate) line number. Opti

binascii.a2b_base64(string) Convert a block of base64 data back to binary and return the binary data. More than one line may be passed at a time.

multiprocessing.connection.deliver_challenge(connection, authkey) Send a randomly generated message to the other end of the connection and wait for a reply. If the reply matches the digest of the message using authkey as the key then a welcome message is sent to the other end of the connection. Otherwise AuthenticationError is raised.

os.supports_dir_fd A Set object indicating which functions in the os module permit use of their dir_fd parameter. Different platforms provide different functionality, and an option that might work on one might be unsupported on another. For consistency’s sakes, functions that support dir_fd always allow specifying the parameter, but will raise an exception if the functionality is not actually available. To check whether a particular function permits use of its dir_fd parameter, use the in op

SSLContext.set_alpn_protocols(protocols) Specify which protocols the socket should advertise during the SSL/TLS handshake. It should be a list of ASCII strings, like ['http/1.1', 'spdy/2'], ordered by preference. The selection of a protocol will happen during the handshake, and will play out according to RFC 7301. After a successful handshake, the SSLSocket.selected_alpn_protocol() method will return the agreed-upon protocol. This method will raise NotImplementedError if HAS_ALPN is False.

coroutine readuntil(separator=b'n') Read data from the stream until separator is found. On success, the data and separator will be removed from the internal buffer (consumed). Returned data will include the separator at the end. Configured stream limit is used to check result. Limit sets the maximal length of data that can be returned, not counting the separator. If an EOF occurs and the complete separator is still not found, an IncompleteReadError exception will be raised, and the internal

Popen.communicate(input=None, timeout=None) Interact with process: Send data to stdin. Read data from stdout and stderr, until end-of-file is reached. Wait for process to terminate. The optional input argument should be data to be sent to the child process, or None, if no data should be sent to the child. The type of input must be bytes or, if universal_newlines was True, a string. communicate() returns a tuple (stdout_data, stderr_data). The data will be bytes or, if universal_newlines was

report_start(out, test, example) Report that the test runner is about to process the given example. This method is provided to allow subclasses of DocTestRunner to customize their output; it should not be called directly. example is the example about to be processed. test is the test containing example. out is the output function that was passed to DocTestRunner.run().