private function process_parameters($param){
    foreach ($param as $key => $val){
      //$val is an array
      if (\is_array($val)){
        $param[$key] = $this->process_parameters($val);
      }
      else {
        $param[$key] = $this->sanitize($val);
      }
    }
    //Return the processed parameters
    return $param;
  }