src/transformers/models/mctct/modeling_mctct.py/MCTCTForCTC/__init__
class MCTCTForCTC:    def __init__(self, config):
        super().__init__(config)

        self.mctct = MCTCTModel(config)

        if config.vocab_size is None:
            raise ValueError(
                f"You are trying to instantiate {self.__class__} with a configuration that "
                "does not define the vocabulary size of the language model head. Please "
                "instantiate the model as follows: `MCTCTForCTC.from_pretrained(..., vocab_size=vocab_size)`. "
                "or define `vocab_size` of your model's configuration."
            )
        output_hidden_size = config.hidden_size

        self.ctc_head = nn.Linear(output_hidden_size, config.vocab_size)

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