def fold(path):
import os
if os.path.isfile(path):
raise IOError("Parameter must be a directory, not a file")
else:
if path[-1]!=os.sep:
path+=os.sep
t=os.listdir(path)
tt=[]
while t!=[]:
for i in t:
n=path+i
if not os.path.isdir(n):
tt.append(n)
t.remove(i)
else:
t.remove(i)
tt.append(n+os.sep)
for k in os.listdir(n+os.sep):
t.append(i+os.sep+k)
return tt