code: def validate(self):
          
          try:
              assert isinstance(self.source_domain, str), "Channel domain must be a string"
              assert self.language, "Channel must have a language"
              return super(ChannelNode, self).validate()
          except AssertionError as ae:
              raise InvalidNodeException("Invalid channel ({}): {} - {}".format(ae.args[0], self.title, self.__dict__))
docs: validate: Makes sure channel is valid
              Args: None
              Returns: boolean indicating if channel is valid