def _rnn_param_concat(*data, **kwargs):
    """
    This function support variable length of positional input.

    Parameters
    ----------
    data : Symbol[]
        List of arrays to concatenate
    dim : int, optional, default='1'
        the dimension to be concated.

    name : string, optional.
        Name of the resulting symbol.

    Returns
    -------
    Symbol
        The result symbol.
    """
    return 0,
