============ Python Program ============
import shelve
import system
fs = shelve.open('filesystem.fs', writeback=True)
current_dir = []
def install(fs):
# create root and others
username = raw_input('What do you want your username to be? ')
fs[""] = {"System": {}, "Users": {username: {}}}
def current_dictionary():
"""Return a dictionary representing the files in the current directory"""
d = fs[""]
for key in current_dir:
d = d[key]
return d