code: def add(self, networkipv4_id, ipv4_id):
          
  
          data = dict()
  
          data['networkipv4'] = networkipv4_id
          data['ipv4'] = dict()
          data['ipv4']['id'] = ipv4_id
          uri = 'api/dhcprelayv4/'
          return self.post(uri, data=data)
docs: List all DHCPRelayIPv4.
  
          :param: networkipv4_id, ipv4_id
  
          :return: Following dictionary:
            {
            "networkipv4": <networkipv4_id>,
            "id": <id>,
            "ipv4": {
                "oct4": <oct4>,
                "oct2": <oct2>,
                "oct3": <oct3>,
                "oct1": <oct1>,
                "ip_formated": "<string IPv4>",
                "networkipv4": <networkipv4_id>,
                "id": <ipv4_id>,
                "descricao": "<string description>"
            }
  
          :raise NetworkAPIException: Falha ao acessar fonte de dados