code: def popall(self, key):
          
          values = self.getall(key)
          try:
              del self[key]
          except KeyError:
              pass
          return values
docs: Remove specified key and return all corresponding values.
          
          If they key is not found, an empty list is return.
          
          >>> m = MutableMultiMap([('a', 1), ('b', 2), ('b', 3), ('c', 4)])
          >>> m.popall('a')
          [1]
          >>> m.popall('b')
          [2, 3]
          >>> m.popall('x')
          []