[BUG] Data overwrite in Celeb-DF-v1 dataset processing

[Coming98]

File: preprocessing/rearrange.py
Line: 259 - 278

The code overwrites previously processed data when handling multiple folders with the same label. Specifically, when processing 'YouTube-real' after 'Celeb-real', both folders map to the same label 'CelebDFv1_real'. The line:

pythondataset_dict[dataset_name][label] = {}

reinitializes the dictionary, completely erasing all data from the 'Celeb-real' folder that was processed earlier.