First the data Dragon for league data needs to be downloaded:
https://riot-api-libraries.readthedocs.io/en/latest/ddragon.html

I originally started with darknet for YoloV3 but found it hard to work with, so I went for a different implementation
https://pjreddie.com/darknet/

I also used this tutorial to understand yolov3 and used their tutorial code: 
https://blog.paperspace.com/how-to-implement-a-yolo-v3-object-detector-from-scratch-in-pytorch-part-4/
Also give credit to the OG League AI:

https://github.com/Oleffa/LeagueAI