PyMOTW: pickle and cPickle

The pickle module implements an algorithm for turning an arbitrary
Python object into a series of bytes (“serializing” the object). The
byte stream can then be transmitted or stored, and later reconstructed
to create a new object with the same characteristics.

The cPickle module implements the same algorithm, in C instead of
Python. It is many times faster than the Python implementation, but does
not allow the user to subclass from Pickle. If sub-classing is not
important for your use, you probably want to use cPickle.

Read more at pickle

PyMOTW: os

The os module provides a wrapper for platform specific modules such as
posix, nt, and mac. The API for functions available on all
platform should be the same, so using the os module offers some
measure of portability. Not all functions are available on all
platforms, however. Many of the process management functions
described in this summary are not available for Windows.

Read more at os

PyMOTW: locale

The locale module is part of Python’s internationalization and
localization support library. It provides a standard way to handle
operations that may depend on the language or location of your users.
For example, formatting numbers as currency, comparing strings for
sorting, and working with dates. It does not cover translation (see the
gettext module) or Unicode encoding.

Read more at locale

PyMOTW: logging

The logging module defines a standard API for reporting errors and
status information from all of your modules. The key benefit of having
the logging API provided by a standard library module is that all python
modules can participate in logging, so your application log can include
messages from third-party modules.

Read more at logging

PyMOTW: linecache

The linecache module is used extensively throughout the Python
standard library when dealing with Python source files. The
implementation of the cache simply holds the contents of files, parsed
into separate lines, in a dictionary in memory. The API returns the
requested line(s) by indexing into a list. The time savings is from
(repeatedly) reading the file and parsing lines to find the one
desired. This is especially useful when looking for multiple lines
from the same file, such as when producing a traceback for an error

Read more at linecache