Modifications for training on custom dataset

[hygxy]

Hey, I have a custom dataset that has 25 classed(Id from 1,2,3,5,...26). I changed line 87 in samples/coco/coco.py to "NUM_CLASSED = 1 + 25" and second cell in train.ipynb to "train_classes = np.array(range(1,26))". Now I am having the error "max() arg is an empty sequence" when running the third cell in train.ipynb.

Which modifications are necessary for training this model on custom dataset, thanks!