GraphQL\Validator\Rules\UniqueDirectivesPerLocation::duplicateDirectiveMessage PHP Method

    static function duplicateDirectiveMessage($directiveName)
    {
        return 'The directive "' . $directiveName . '" can only be used once at this location.';
    }

 private function duplicateDirective($directiveName, $l1, $c1, $l2, $c2)
 {
     return ['message' => UniqueDirectivesPerLocation::duplicateDirectiveMessage($directiveName), 'locations' => [['line' => $l1, 'column' => $c1], ['line' => $l2, 'column' => $c2]]];
 }