code: public function addFilter($keyName)
      {
          if (!$keyName instanceof Filter\FilterInterface) {
              $keyName = new Filter($keyName);
          }
  
          $this->parameterFilters[] = $keyName;
          return $this;
      }
docs: Adds an entry to a black list of GET/POST parameter key names which
  should not be sent to the Airbrake server. This should be used to prevent
  sensitive information, such as passwords or credit card details from
  leaving your application server via error logging.
  
  Nested keys are treated like html form names - e.g. the key name
  my_form[id] would stop the value inside $_POST['my_form']['id']
  from being sent.
  
  @param string|Filter\FilterInterface $keyName
  @return self