@NotNull
  public static MavenModel convertModel(Model model) {
    if(model.getBuild() == null) {
      model.setBuild(new Build());
    }
    Build build = model.getBuild();
    return convertModel(model,
                        asSourcesList(build.getSourceDirectory()),
                        asSourcesList(build.getTestSourceDirectory()));
  }
@NotNull
  public static MavenModel convertModel(Model model)