Incorrect adjustment sets

[futtetennista]

Minimal examples

dag = CausalGraphicalModel(
    nodes=["E", "U", "W"],
    edges=[("E", "W"), ("U", "W")],
)
dag.get_all_backdoor_adjustment_sets("E", "W")
# expected: {frozenset()}
# actual: {frozenset(), frozenset({'U'})}

I double checked this in R using daggity and this is the result

> dag <- dagitty( "dag{ e -> w ; u -> w }" ) ;  adjustmentSets(dag,exposure="e",outcome="w")
{}