def METHOD_NAME(self, index, item):
    # If the item exists in the filtered list, track that it is being
    # removed; but don't propagate the removal notification until it has
    # been removed from the base data source
    for i, filtered_item in enumerate(self._filtered()):
        if filtered_item == item:
            # Track that the object *was* in the data source
            self._removals[item] = i