code: def clear_weights(self):
          ''' clear weights of the graph
          '''
          self.weighted = False
          for layer in self.layer_list:
              layer.weights = Nonf clear_weights(self):
          ''' clear weights of the graph
          '''
          self.weighted = False
          for layer in self.layer_list:
              layer.weights = None
docs: clear weights of the graph