Python is retarded. Brain-damaged scope rules make it hard to write closures. Compare the following. I hate you Guido, and your cult.

def poo():
  x=42
  def moo():
     x += 1
    return x
  return moo

m=poo()
print m

> UnboundLocalError: local variable 'x' referenced before assignment

versus

def poo():
   x=[42]
   def moo():
      x[0]+=1
      return x[0]
   return moo

m=poo()
print m

> 43