protected function hasInputIdentifier(
        ResourceTransformer $transformer,
        ResourceDefinition $resourceDefinition,
        Context $context,
        &$input
    ) {
        $identifiers = $resourceDefinition->getFields()->getIdentifiers();
        if (count($identifiers) > 0) {
            foreach ($identifiers as $field) {
                try {
                    $value = $this->resolvePropertyInput($transformer, $input, $field, $context);
                    if (!$value) {
                        return false;
                    }
                } catch (ValueUndefined $e) {
                    return false;
                }
            }
            return true;
        }
        return false;
    }