Creates the efficientdet model specified by `model_name`.
efficientdet_model(model_name, num_classes, img_size, pretrained = TRUE)
Specifies the model to create. For pretrained models, check [this](https://github.com/rwightman/efficientdet-pytorch#models) table.
Number of classes of your dataset (including background).
Image size that will be fed to the model. Must be squared and divisible by 128.
If TRUE, use a pretrained backbone (on COCO).
model