def port_range(range):
    """
    :param range:  openstack port range format '200: 300'
    :return: fortigate port range format: '100-200'
    e.g. tcp-portrange 100-200:300-400
    """
    if range:
        return '-'.join([p.strip() for p in range.split(':')])
    else:
        return '1-65535'