Diffusers version: 0.33.0.dev0
The version should be the development version, but as a problem that sometimes occurs with Diffusers, the development version version remains the same for a while, so it is not updated with pip install -U. You can update it by uninstalling it once.
pip uninstall diffusers
pip install git+https://github.com/huggingface/diffusers
Also, the import method may change slightly depending on the library version.