message: [Python]: fix seq_length
diff: @@ -187,18 +187,20 @@ flexflow_model_prefetch(
  void
  flexflow_model_forward(
  - flexflow_model_t handle_)
  + flexflow_model_t handle_,
  + int seq_length)
  {
  FFModel *handle = FFCObjectWrapper::unwrap(handle_);
  - handle->forward();
  + handle->forward(seq_length);
  }
  void
  flexflow_model_backward(
  - flexflow_model_t handle_)
  + flexflow_model_t handle_,
  + int seq_length)
  {
  FFModel *handle = FFCObjectWrapper::unwrap(handle_);
  - handle->backward();
  + handle->backward(seq_length);
  }
  void
  