'get all vlan vid list, sample: [ "20", "30", "31" ]'

def get_vlans_list(self):

    conf_str = CE_NC_GET_VLANS
    xml_str = get_nc_config(self.module, conf_str)
    vlan_list = list()
    if ('<data/>' in xml_str):
        return vlan_list
    else:
        vlan_list = re.findall('.*<vlanId>(.*)</vlanId>.*', xml_str)
        return vlan_list
