docs: public static ConceptId getResourceEdgeId(TransactionOLTP graph, ConceptId conceptId1, ConceptId conceptId2) {
          if (mayHaveResourceEdge(graph, conceptId1, conceptId2)) {
              Optional<Concept> firstConcept = graph.stream(Graql.match(
                      var("x").id(conceptId1.getValue()),
                      var("y").id(conceptId2.getValue()),
                      var("z").rel(var("x")).rel(var("y")))
                      .get("z"))
                      .map(answer -> answer.get("z"))
                      .findFirst();
              if (firstConcept.isPresent()) {
                  return firstConcept.get().id();
              }
          }
          return null;
      }