ArtifactSpec b1 = a.addDependency("b", "1.0");
        ArtifactSpec c = a.addDependency("c", "1.0");
        ArtifactSpec d2 = b1.addDependency("d", "2.0");
        d2.addDependency("h", "1.0");
        ArtifactSpec d1 = c.addDependency("d", "1.0");
        ArtifactSpec b2 = c.addDependency("b", "2.0");
        ArtifactSpec e = b2.addDependency("e", "1.0");

        //
        public ProjectBuilder addDependency(String groupId, String artifactId, String version, String scope) {
            return addDependency(groupId, artifactId, version, scope, (Exclusion) null);
        }

        public ProjectBuilder addDependency(
                String groupId, String artifactId, String version, String scope, Exclusion exclusion) {