def cat_to_veto_def_cat(val):
    """ Convert a category character to the corresponding value in the veto
    definer file.

    Parameters
    ----------
    str : single character string
        The input category character

    Returns
    -------
    pipedown_str : str
        The pipedown equivalent notation that can be passed to programs
    that expect this definition.
    """
    if val == '1':
        return 1
    if val == '2':
        return 2
    if val == '3':
        return 4
    if val == 'H':
        return 3
    else:
        raise ValueError('Invalid Category Choice')
