Bring value from walk()

[Milos Prudek]

I need a function that walks the dir tree and adds up occupied space.
This is the source. "print Dirn", "print '-',X,Fs" and "print End of
walk..." lines are for debugging only.

The problem is that Filespace is Zero at the end. Fs is reset to Zero
every time walk gets called, so I thought I would add Total variable
(lines with Total are currently commented out), but I got NameError:
Total. 

Is there (an object oriented) way to bring Total from Estimatespace thru
EstDirSpace right back into main program?

def Estimatespace(Fs, Dirn, Nams):
    print Dirn
    for X in Nams:
        Fs=Fs+os.stat(Dirn+'/'+X)[stat.ST_SIZE]
        print '-',X,Fs
    # Total=Total+Fs
    return

def EstDirSpace(RootDir):
    Filespace=0
    # Total=0
    os.path.walk(RootDir, Estimatespace, Filespace)
    print "end of walk, Filespace=",Filespace
    return Filespace

EstSpace=EstDirSpace('c:/DL/ati')

--
Milos Prudek