• Follow PEP 8
• All code should be Python 3 compliant
• Use 4 spaces for indentation, do not use tabs
• Only import what you really need
• Limit lines to 79 characters (it's in PEP 8 :)); the only exceptions are pyfaf.storage objects - keep it one attribute per line
• Use if x is None: and if x is not None: rather than if x:, if not x: or if not x is None:
• Use FafError or its subclass when raising an exception related to faf.
• For strings, use double quotes rather than single quotes - "string" rather than 'string'.
• Use __all__ for exporting functions and constants from modules.
• Use docstrings for all functions, exported methods and constants.
• Executables should be minimal. Most of the code should be present in core module so it's possible to test and reuse it easily.

Comment style

• Follow PEP 257
• Use double quotes.
• One empty line after comment.
• Comments should start on empty line for better readability.

Comments with argument/return value/exceptions specification: Either http://sphinx-doc.org/domains.html#info-field-lists or style used by google http://pythonhosted.org/an_example_pypi_project/sphinx.html#full-code-example