StatusOr<TaggedValue> Function::Execute(AbstractContext* ctx,
                                        TaggedValue value) const {
  TF_RETURN_IF_ERROR(VerifySupportedArgs(value));
  TF_ASSIGN_OR_RETURN(auto concrete_fn, GetConcreteFunction(value));
  std::vector<AbstractTensorHandle*> args;
  Flatten(value, &args);
  std::vector<AbstractTensorHandle*> outs(
      GetFlatSize(concrete_fn.output_signature));
  TF_RETURN_IF_ERROR(