src/transformers/models/fnet/modeling_fnet.py/FNetForNextSentencePrediction/__init__
class FNetForNextSentencePrediction:    def __init__(self, config):
        super().__init__(config)

        self.fnet = FNetModel(config)
        self.cls = FNetOnlyNSPHead(config)

        # Initialize weights and apply final processing
        self.post_init()