def getQueriables():
    """Return an iterable of objects that can be queried

        The returned obects should be two-tuples with:

        - A unicode id

          The id must uniquely identify the queriable object within
          the set of queriable objects. Furthermore, in subsequent
          calls, the same id should be used for a given queriable
          object.

        - A queriable object

          This is an object for which there is a view provided for
          searching for items.

        """
