def childfree_tree_factory(self):
        """
        Fixture for a child-free DataTree factory.
        """
        from random import randint

        def _childfree_tree_factory():
            return xr.DataTree(
                dataset=xr.Dataset({"z": ("y", [randint(1, 100) for _ in range(3)])})
            )

        return _childfree_tree_factory

        Fixture for a child-free DataTree factory.
        
xarray/tests/test_formatting_html.py