if ty == TFRTypes.SHAPE and node.attr == 'as_list':
        return (value, TFRTypes.TF_TENSOR_SHAPE_FUNC)

    raise NotImplementedError('Attribute kind not recognized.')

  def visit_Assign(self, node):
    values = self.visit(node.value)
    if isinstance(node.targets[0], ast.Tuple):
      targets = [elt.id for elt in node.targets[0].elts]
    elif isinstance(node.targets[0], ast.Name):