if (!isSuccessorOf(stepToExecuteBefore)) {
            predecessors.add(stepToExecuteBefore);
            stepToExecuteBefore.successors.add(this);
        }
    }

    public void executeBefore(BuildStep stepToExecuteAfter) {
        stepToExecuteAfter.executeAfter(this);
    }

    public Stream<MojoExecution> executions() {
        return mojos.values().stream().flatMap(m -> m.values().stream());

                        project.getCollectedProjects().forEach(p -> {
                            // 1. Child's phase start waits for parent's phase start
                            plan.step(p, BEFORE + n2).ifPresent(before::executeBefore);
                            // 2. Parent's phase completion waits for child's phase completion
                            plan.step(p, AFTER + n2).ifPresent(after::executeAfter);
                        });