'get the VPN instance associated with the interface'

def get_interface_vpn(self):

    xml_str = CE_NC_GET_VRF_INTERFACE
    con_obj = get_nc_config(self.module, xml_str)
    if ('<data/>' in con_obj):
        return
    xml_str = con_obj.replace('\r', '').replace('\n', '').replace('xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"', '').replace('xmlns="http://www.huawei.com/netconf/vrp"', '')
    root = ElementTree.fromstring(xml_str)
    vpns = root.findall('data/l3vpn/l3vpncomm/l3vpnInstances/l3vpnInstance')
    if vpns:
        for vpnele in vpns:
            vpn_name = None
            for vpninfo in vpnele:
                if (vpninfo.tag == 'vrfName'):
                    vpn_name = vpninfo.text
                if (vpninfo.tag == 'l3vpnIfs'):
                    self.get_interface_vpn_name(vpninfo, vpn_name)
    return
