@@ -471,6 +471,21 @@ def adjust(command = None, dim = 1, parent = None, **kw):
vg.pack(expand = 1, fill = 'x')
return vg
+def difference(a, b):
+ """
+ difference(list, list):
+ if not a: return b
+ if not b: return a
+ d = []
+ for i in a:
+ if (i not in b) and (i not in d):
+ d.append(i)
+ for i in b:
+ if (i not in a) and (i not in d):
+ return d
+
def intersection(a, b):
"""
intersection(list, list):