Returns list of matching VRFs

        Includes "virtual" VRF 'all' which is used in search
        operations

def complete_vrf_virtual(arg):
    """ Returns list of matching VRFs

        Includes "virtual" VRF 'all' which is used in search
        operations
    """

    ret = complete_vrf(arg)

    search_string = ''
    if arg is not None:
        search_string = '^%s' % arg

    if re.match(search_string, 'all'):
        ret.append('all')

    return ret