code: def extend(self, item):
          
          if not isinstance(item, list):
              raise TypeError(
                  'You can only extend lists with lists. '
                  'You supplied \"%s\"' % type(item))
          for entry in item:
              if not isinstance(entry, str):
                  raise TypeError(
                      'Members of this object must be strings. '
                      'You supplied \"%s\"' % type(entry))
              list.append(self, entry)
docs: Extend the list with another list. Each member of the list must be
          a string.