The character used by the OS to separate pathname components,
e.g. "/" for POSIX or ":" for the Macintosh.
Note that knowing this is not sufficient to be able to parse or
concatenate pathnames -- use os.path.split() and
os.path.join() -- but it is occasionally useful.
An alternative character used by the OS to separate pathname components,
or None if only one separator character exists. This is set to
"/" on DOS and Windows systems where sep is a backslash.
The string used to separate (or, rather, terminate) lines on the
current platform. This may be a single character,
e.g. '\n' for POSIX or '\r' for MacOS, or multiple
characters, e.g. '\r\n' for MS-DOS and MS Windows.