@Nullable
  public static PsiType getLeastUpperBoundNullable(@Nullable PsiType type1, @Nullable PsiType type2, @NotNull PsiManager manager) {
    if (type1 == null) return type2;
    if (type2 == null) return type1;
    return getLeastUpperBound(type1, type2, manager);
  }
@Nullable
  public static PsiType getLeastUpperBoundNullable(@Nullable PsiType type1, @Nullable PsiType type2, @NotNull PsiManager manager)