code: def add(self, dpid, ports):
          
          assert isinstance(ports, list)
          assert len(ports) >= 2
          ifs = {}
          for port in ports:
              ifs[port] = {'enabled': False, 'timeout': 0}
          bond = {dpid: ifs}
          self._bonds.append(bond)
docs: add a setting of a bonding i/f.
          'add' method takes the corresponding args in this order.
  
          ========= =====================================================
          Attribute Description
          ========= =====================================================
          dpid      datapath id.
  
          ports     a list of integer values that means the ports face
                    with the slave i/fs.
          ========= =====================================================
  
          if you want to use multi LAG, call 'add' method more than once.