/**
  * Return a list of the contracts this party is associated with
  *
  * @return a list of rental_contract objects
  */
 public function get_contracts()
 {
     $so = self::get_so();
     if (!$this->contracts) {
         $this->contracts = rental_contract::get_contracts_for_tentant($this->get_id);
     }
     return $this->contracts;
 }