public function get_annuity_label()
 {
     require_once 'class-ct1-annuity.php';
     $a = new CT1_Annuity();
     $a->set_term($this->get_term());
     return $this->get_coupon() . $a->get_label() . " + v^{ " . $this->get_term() . "}";
 }
 public function get_labels()
 {
     $labels = parent::get_labels();
     $labels['CT1_Mortgage'] = $this->label_mortgage();
     return $labels;
 }
 public function get_labels()
 {
     $labels = parent::get_labels();
     $labels['CT1_Annuity_Increasing'] = $this->label_annuity_increasing();
     return $labels;
 }
 public function get_labels()
 {
     $labels = parent::get_labels();
     $labels['CT1_Annuity'] = $this->label_annuity();
     return $labels;
 }