def _get_auxmodel_id(line: str, uline: str) ->int:
    """
    parses the superelement header::

        BEGIN AUXMODEL=2
        BEGIN BULK AUXMODEL=2
        BEGIN BULK AUXMODEL = 2

    """
    sline = uline.split('=')
    try:
        auxmodel_id = int(sline[1])
    except (IndexError, ValueError):
        msg = 'expected "BEGIN AUXMODEL=1"\nline = %s' % line
        raise SyntaxError(msg)
    if auxmodel_id < 0:
        raise SyntaxError('auxmodel_id=%i must be greater than 0; line=%s' %
            (auxmodel_id, line))
    return auxmodel_id
