private List<PsiPackage> getSubpackagesList(final String parentName) {
    assertValid();
    List<PsiPackage> psiPackages = myPackageToSubpackagesMap.get(parentName);
    if (psiPackages == null) {
      psiPackages = new ArrayList<>();
      myPackageToSubpackagesMap.put(parentName, psiPackages);
    }
    return psiPackages;
  }
private List<PsiPackage> getSubpackagesList(final String parentName)