A quick and tolerant directory validator for unix systems in Python

validate_directory.py

import os

"""
validate_directory: string -> string
given a string that represents a directory, this function will go through and
do some basic validation on it. If there is a problem with the directory as
given, it will be converted to the home directory and returned as is.
"""
def validate_directory(directory=None):
	if directory == None or directory == '~' or not os.path.isdir(directory):
		# if there is a problem, the default is the home directory
		return os.path.expanduser('~')

	return os.path.abspath(directory)