plan.put(project, steps);
    }

    public void addStep(MavenProject project, String name, BuildStep step) {
        plan.get(project).put(name, step);
    }

    public Stream<BuildStep> allSteps() {
        return plan.values().stream().flatMap(m -> m.values().stream());
    }

    public Stream<BuildStep> steps(MavenProject project) {
        return Optional.ofNullable(plan.get(project))

        private void checkUnboundVersions(BuildPlan buildPlan) {
            String defaulModelId = DefaultLifecycleRegistry.DEFAULT_LIFECYCLE_MODELID;
            List<String> unversionedPlugins = buildPlan
                    .allSteps()
                    .flatMap(step -> step.mojos.values().stream().flatMap(map -> map.values().stream()))
                    .map(MojoExecution::getPlugin)
                    .filter(p -> p.getLocation("version") != null