You can call the os.listdir function to get the list of the directory contents and use the sorted function to sort this list.
For example
>>> import os
>>> list_dir = os.listdir('.')
>>> list_dir = [f.lower() for f in list_dir] # Convert to lower case
>>> sorted(list_dir)
['dlls', 'doc', 'etc', 'include', 'lib', 'libs', 'license.txt', 'news.txt', 'python.exe', 'pythonw.exe', 'readme.txt', 'scripts', 'share', 'tcl', 'tools', 'w9xpopen.exe']