Add support for ReduceLROnPlateau lr_scheduler & Reformat to pass Flake8

[MohamedA95]

Add support for ReduceLROnPlateau lr_scheduler & reformat file to pass Flake8 check

Example config: "lr_scheduler": { "type": "ReduceLROnPlateau", "args": { "mode": "max", "factor": 0.1, "verbose": true }, "metric": "accuracy" }