code: def p_kw_args_update(self, p):
          
          p[0] = p[1]
          for key in p[3]:
              if key in p[1]:
                  msg = "Keyword argument '%s' defined more than once." % key
                  self.errors.append((msg, p.lineno(2), self.path))
          p[0].update(p[3])
docs: kw_args : kw_args COMMA kw_arg