* add flake 8 check
* split up litellm _acompletion
* fix get model client
* refactor use commong func to add metadata to kwargs
* use common func to get timeout
* re-use helper to _get_async_model_client
* use _handle_mock_testing_rate_limit_error
* fix docstring for _handle_mock_testing_rate_limit_error
* fix function_with_retries
* use helper for mock testing fallbacks
* router - use 1 func for simple_shuffle
* add doc string for simple_shuffle
* use 1 function for filtering cooldown deployments
* fix use common helper to _get_fallback_model_group_from_fallbacks