code: def dump(self, human=False):
          
          txt = str(self)
          if human:
              txt = txt.replace(", '", ",\n'")
              txt = txt.replace("{", "{\n")
              txt = txt.replace("}", "\n}")
              txt = txt.replace("[", "[\n")
              txt = txt.replace("]", "\n]")
          return txt
docs: 将自身内容打印成字符串
  
          :param bool human: 若值为 True ，则打印成易读格式。