code: def list_folder(self, folder="/", describe=False, only="all", includeHidden=False, **kwargs):
          
          # TODO: it would be nice if we could supply describe
          # fields/defaultFields in a similar way to what we pass to the
          # high-level describe method, rather than having to construct
          # the literal API input
  
          api_method = dxpy.api.container_list_folder
          if isinstance(self, DXProject):
              api_method = dxpy.api.project_list_folder
  
          return api_method(self._dxid, {"folder": folder,
                                         "describe": describe,
                                         "only": only,
                                         "includeHidden": includeHidden},
                            **kwargs)
docs: :param folder: Full path to the folder to list
          :type folder: string
          :param describe: If True, returns the output of ``/describe`` on each object (see below for notes)
          :type describe: bool or dict
          :param only: Indicate "objects" for only objects, "folders" for only folders, or "all" for both
          :type only: string
          :param includeHidden: Indicate whether hidden objects should be returned
          :type includeHidden: bool
          :returns: A hash with key "objects" for the list of object IDs and key "folders" for the list of folder routes
          :rtype: dict
  
          Returns a hash containing a list of objects that reside directly
          inside the specified folder, and a list of strings representing
          the full paths to folders that reside directly inside the
          specified folder.
  
          By default, the list of objects is provided as a list containing
          one hash ``{"id": "class-XXXX"}`` with the ID of each matching
          object. If *describe* is not False, the output of ``/describe``
          is also included in an additional field "describe" for each
          object. If *describe* is True, ``/describe`` is called with the
          default arguments. *describe* may also be a hash, indicating the
          input hash to be supplied to each ``/describe`` call.