src/transformers/models/transfo_xl/tokenization_transfo_xl.py/LMMultiFileIterator/__init__
class LMMultiFileIterator:    def __init__(self, paths, vocab, bsz, bptt, device="cpu", ext_len=None, shuffle=False):
        self.paths = paths
        self.vocab = vocab

        self.bsz = bsz
        self.bptt = bptt
        self.ext_len = ext_len if ext_len is not None else 0

        self.device = device
        self.shuffle = shuffle