/**
  *   Build question object by id
  *
  *   @param  $question_id = question_id that you want to select
  *   @return question object, false if not found
  **/
 public function get_question_by_id($question_id)
 {
     self::$question = $this->select_question_by_id($question_id);
     if (self::$question !== false) {
         self::$question = $this->set_question_object_values();
     }
     return self::$question;
 }