code: def repr(self, changed_widgets=None):
          
          if changed_widgets is None:
              changed_widgets={}
          local_changed_widgets = {}
          self._set_updated()
          return ''.join(('<', self.type, '>\n', self.innerHTML(local_changed_widgets), '\n</', self.type, '>'))
docs: It is used to automatically represent the object to HTML format
          packs all the attributes, children and so on.
  
          Args:
              changed_widgets (dict): A dictionary containing a collection of tags that have to be updated.
                  The tag that have to be updated is the key, and the value is its textual repr.