directory listing

[SU News Server]

I've struggled with this for quite a while and I'm am just not sure 
what is going on. I have the following code
import os

def buildList( directory='/Users/mkonrad' )

	dirs = [ ]

	listing = os.listdir(directory)

   for x in listing:
      if os.path.isdir(x):
			dirs.append(x)

	return dirs

This always returns an empty list.
Now if I change it so that directory='.' or directory=os.getcwd()
Then it returns a list of directories. 

Any ideas?

Thank you,
-Michael