code: def get(self, interface_id, interface_ip=None):
           
          interfaces = []
          for interface in iter(self):
              if interface.interface_id == str(interface_id):
                  if interface_ip:
                      if interface.interface_ip == interface_ip:
                          return interface
                  else:
                      interfaces.append(interface)
          return interfaces
docs: Get will return a list of interface references based on the
          specified interface id. Multiple references can be returned if
          a single interface has multiple IP addresses assigned.
          
          :return: If interface_ip is provided, a single ContactAddressNode
              element is returned if found. Otherwise a list will be
              returned with all contact address nodes for the given
              interface_id.