code: def valid_api_plugin(self, plugin):
          
          if (issubclass(plugin, APIPlugin)       and
              hasattr(plugin, 'plugin_type')      and plugin.plugin_type == 'api' and
              hasattr(plugin, 'request')          and plugin.request != None and
              hasattr(plugin, 'request_class')    and plugin.request_class != None and
              hasattr(plugin, 'response_class')   and plugin.response_class != None):
              return True
          return False
docs: Validate an API plugin, ensuring it is an API plugin and has the
          necessary fields present.
  
          `plugin` is a subclass of scruffy's Plugin class.