code: def pop(self, key, *args):
          'Remove *key* from maps[0] and return its value. Raise KeyError if *key* not in maps[0].'
          try:
              return self.maps[0].pop(key, *args)
          except KeyError:
              raise KeyError('Key not found in the first mapping: {!r}'.format(key)f pop(self, key, *args):
          'Remove *key* from maps[0] and return its value. Raise KeyError if *key* not in maps[0].'
          try:
              return self.maps[0].pop(key, *args)
          except KeyError:
              raise KeyError('Key not found in the first mapping: {!r}'.format(key))
docs: Remove *key* from maps[0] and return its value. Raise KeyError if *key* not in maps[0].