def _get_view_index(self, view):
        """Index of a view in the GUI: 0 for the first view of a given
        class, 1 for the next, and so on."""
        name = view.__class__.__name__
        return len(self.list_views(name))
Index of a view in the GUI: 0 for the first view of a given
        class, 1 for the next, and so on.