code: def add(self, interface_id, virtual_mapping=None,
              virtual_resource_name=None, zone_ref=None, comment=None):
          
          interface = Layer3PhysicalInterface(engine=self._engine,
              interface_id=interface_id, zone_ref=zone_ref,
              comment=comment, virtual_resource_name=virtual_resource_name,
              virtual_mapping=virtual_mapping)
          
          return self._engine.add_interface(interface)
docs: Add single physical interface with interface_id. Use other methods
          to fully add an interface configuration based on engine type.
          Virtual mapping and resource are only used in Virtual Engines.
  
          :param str,int interface_id: interface identifier
          :param int virtual_mapping: virtual firewall id mapping
                 See :class:`smc.core.engine.VirtualResource.vfw_id`
          :param str virtual_resource_name: virtual resource name
                 See :class:`smc.core.engine.VirtualResource.name`
          :raises EngineCommandFailed: failure creating interface
          :return: None