@staticmethod
def linker(fn):
    """Tag the method as a "linked to attribute" event handler.

        This optional event handler will be called when the collection class
        is linked to or unlinked from the InstrumentedAttribute.  It is
        invoked immediately after the '_sa_adapter' property is set on
        the instance.  A single argument is passed: the collection adapter
        that has been linked, or None if unlinking.

        .. deprecated:: 1.0.0 - the :meth:`.collection.linker` handler
           is superseded by the :meth:`.AttributeEvents.init_collection`
           and :meth:`.AttributeEvents.dispose_collection` handlers.

        """
    fn._sa_instrument_role = 'linker'
    return fn
