'is vrf route distinguisher exist'

def is_vrf_rd_exist(self):

    if (not self.vrf_af_info):
        return False
    for vrf_af_ele in self.vrf_af_info['vpnInstAF']:
        if (vrf_af_ele['afType'] == self.vrf_aftype):
            if (vrf_af_ele['vrfRD'] is None):
                return False
            if (self.route_distinguisher is not None):
                return bool((vrf_af_ele['vrfRD'] == self.route_distinguisher))
            else:
                return True
        else:
            continue
    return False
