@Contract("_, null -> null; _, !null -> !null")
  public static DfaVariableValue createThisValue(@NotNull DfaValueFactory factory, @Nullable PsiClass aClass) {
    if (aClass == null) return null;
    return factory.getVarFactory().createVariableValue(new ThisDescriptor(aClass));
  }
@Contract("_, null -> null; _, !null -> !null")
  public static DfaVariableValue createThisValue(@NotNull DfaValueFactory factory, @Nullable PsiClass aClass)