/**
  * Returns the donation ID.
  *
  * @return  int
  * @access  public
  * @since   1.0.0
  */
 public function get_donation_id()
 {
     if (!$this->has_valid_donation()) {
         return '';
     }
     return $this->donation->get_donation_id();
 }
 /**
  * Returns the donation ID. 
  *
  * @return  int
  * @access  public
  * @since   1.0.0
  */
 public function get_donation_id()
 {
     return $this->return_value_if_has_valid_donation($this->donation->get_donation_id());
 }