def get_regulatory_pairs(graph: BELGraph) -> Set[NodePair]:
cg = get_causal_subgraph(graph)<EOL>results = set()<EOL>for u, v, d in cg.edges(data=True):<EOL><INDENT>if d[RELATION] not in CAUSAL_INCREASE_RELATIONS:<EOL><INDENT>continue<EOL><DEDENT>if cg.has_edge(v, u) and any(dd[RELATION] in CAUSAL_DECREASE_RELATIONS for dd in cg[v][u].values()):<EOL><INDENT>results.add((u, v))<EOL><DEDENT><DEDENT>return results<EOL>
Find pairs of nodes that have mutual causal edges that are regulating each other such that ``A -> B`` and
    ``B -| A``.

    :return: A set of pairs of nodes with mutual causal edges