@in_place_transformation<EOL>def remove_unweighted_leaves(graph: BELGraph, key: Optional[str] = None) -> None:
unweighted_leaves = list(get_unweighted_upstream_leaves(graph, key=key))<EOL>graph.remove_nodes_from(unweighted_leaves)<EOL>
Remove nodes that are leaves and that don't have a weight (or other key) attribute set.

    :param graph: A BEL graph
    :param key: The key in the node data dictionary representing the experimental data. Defaults to
     :data:`pybel_tools.constants.WEIGHT`.