src/transformers/models/fnet/modeling_fnet.py/FNetLayer/__init__
class FNetLayer:    def __init__(self, config):
        super().__init__()
        self.chunk_size_feed_forward = config.chunk_size_feed_forward
        self.seq_len_dim = 1  # The dimension which has the sequence length
        self.fourier = FNetFourierTransform(config)
        self.intermediate = FNetIntermediate(config)
        self.output = FNetOutput(config)