code: def p_realnamelist(self, p):
          'realnamelist : realnamelist COMMA realname'
          p[0] = p[1] + (p[3],)
          p.set_lineno(0, p.lineno(1)f p_realnamelist(self, p):
          'realnamelist : realnamelist COMMA realname'
          p[0] = p[1] + (p[3],)
          p.set_lineno(0, p.lineno(1))
docs: realnamelist : realnamelist COMMA realname