@staticmethod
def _get_switchboard_kwargs(free_params, prev_switchboard, prev_output_dim):
    """Return the kwargs for the cls '__init__' method.

        Reference implementation, merges input into one single channel.
        Override this method for other switchboard classes.
        """
    in_channel_dim = prev_output_dim // prev_switchboard.output_channels
    return {'input_dim': prev_output_dim, 'connections': list(range(
        prev_output_dim)), 'out_channel_dim': prev_output_dim,
        'in_channel_dim': in_channel_dim}
