def __init__(self, d_input, cell=None, return_output=True, transposed=False, dropout=0.0):
        """
        return_output: if False, only returns the state
        """
        super().__init__()
        self.transposed = transposed
        if dropout > 0.0:
            raise NotImplementedError("Dropout currently not supported for custom RNNs")
        self.return_output = return_output

        self.cell = utils.instantiate(cell_registry, cell, d_input)

        return_output: if False, only returns the state
        
analyze/convnexts4nd/src/models/sequence/rnns/rnn.py