Can't create file in python filesystem
<p>I have this school project to create a virtual filesystem using python. I want to create an add method does not do anything at all.   </p>

<pre><code>import shelve
import sys

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 

def ls(args):

print 'Contents of directory', "/" + "/".join(current_dir) + ':'

for i in current_dictionary():

    print i

def cd(args):

if len(args) != 1:

    print "Usage: cd "
    return

if args[0] == "..":
    if len(current_dir) == 0:
        print "Cannot go above root"
    else:
        current_dir.pop()
elif args[0] not in current_dictionary():
    print "Directory " + args[0] + " not found"
else:
    current_dir.append(args[0])

def mkdir(args):
if len(args) != 1:
    print "Usage: mkdir "
    return

#To create an empty directory there and sync back to shelve dictionary!

d = current_dictionary()[args[0]] = {}
fs.sync()

def pwd(args):

d=current_dir
print d[-1]

def quit(args):
sys.exit(0)

def add(args):
with open("test.txt", 'w') as f:
    f.write("test")

COMMANDS = {'ls' : ls, 'cd': cd, 'mkdir': mkdir,'pwd':pwd,'quit':quit,'add':add}

install(fs)

while True:
raw = raw_input('&gt; ')
cmd = raw.split()[0]
if cmd in COMMANDS:
    COMMANDS[cmd](raw.split()[1:])
</code></pre>

<p>My problem is this method does not do anything. I just want it to create a file in the directory that is active.</p>

<pre><code>def add(args):
with open("test.txt", 'w') as f:
    f.write("test")
</code></pre>