class Stack(list):
    """
    Based on class list to create LIFO Stacks
      pop on call with ()
      push if called with (one or more arguments)
      popall which returns the current stack and clears it
    """
    __init__ = lambda self, *e: self.extend(x for x in e)
    __call__ = lambda s, *e: s.extend(e) if e else s.pop()
    popall = lambda s: (s[:], s.clear())[0]