math.acos(x) Return the arc cosine of x, in radians.

marshal.version Indicates the format that the module uses. Version 0 is the historical format, version 1 shares interned strings and version 2 uses a binary format for floating point numbers. Version 3 adds support for object instancing and recursion. The current version is 4.

marshal.loads(string) Convert the string to a value. If no valid value is found, raise EOFError, ValueError or TypeError. Extra characters in the string are ignored.

marshal.load(file) Read one value from the open file and return it. If no valid value is read (e.g. because the data has a different Python version’s incompatible marshal format), raise EOFError, ValueError or TypeError. The file must be an open file object opened in binary mode ('rb' or 'r+b'). Note If an object containing an unsupported type was marshalled with dump(), load() will substitute None for the unmarshallable type.

marshal.dumps(value[, version]) Return the string that would be written to a file by dump(value, file). The value must be a supported type. Raise a ValueError exception if value has (or contains an object that has) an unsupported type. The version argument indicates the data format that dumps should use (see below).

marshal.dump(value, file[, version]) Write the value on the open file. The value must be a supported type. The file must be an open file object such as sys.stdout or returned by open() or os.popen(). It must be opened in binary mode ('wb' or 'w+b'). If the value has (or contains an object that has) an unsupported type, a ValueError exception is raised — but garbage data will also be written to the file. The object will not be properly read back by load(). The version argument indicates the d

map(function, iterable, ...) Return an iterator that applies function to every item of iterable, yielding the results. If additional iterable arguments are passed, function must take that many arguments and is applied to the items from all iterables in parallel. With multiple iterables, the iterator stops when the shortest iterable is exhausted. For cases where the function inputs are already arranged into argument tuples, see itertools.starmap().

mailcap.getcaps() Returns a dictionary mapping MIME types to a list of mailcap file entries. This dictionary must be passed to the findmatch() function. An entry is stored as a list of dictionaries, but it shouldn’t be necessary to know the details of this representation. The information is derived from all of the mailcap files found on the system. Settings in the user’s mailcap file $HOME/.mailcap will override settings in the system mailcap files /etc/mailcap, /usr/etc/mailcap, and /usr/lo

mailcap.findmatch(caps, MIMEtype, key='view', filename='/dev/null', plist=[]) Return a 2-tuple; the first element is a string containing the command line to be executed (which can be passed to os.system()), and the second element is the mailcap entry for a given MIME type. If no matching MIME type can be found, (None, None) is returned. key is the name of the field desired, which represents the type of activity to be performed; the default value is ‘view’, since in the most common case you s

exception mailbox.NotEmptyError Raised when a mailbox is not empty but is expected to be, such as when deleting a folder that contains messages.