private function isNullIdentifier($identifier)
    {
        if (null === $identifier) {
            return true;
        }

        if ($identifier instanceof Traversable || is_array($identifier)) {
            $nonNullIdentifiers = array_filter(
                ArrayUtils::iteratorToArray($identifier),
                function ($value) {
                    return null !== $value;
                }
            );

            return empty($nonNullIdentifiers);
        }

        return false;
    }
private function isNullIdentifier($identifier)
    {
        if (null === $identifier) {
            return true;
        }

        if ($identifier instanceof Traversable || is_array($identifier)) {
            $nonNullIdentifiers = array_filter(
                ArrayUtils::iteratorToArray($identifier),
                function ($value) {
                    return null !== $value;
                }
            );

            return empty($nonNullIdentifiers);
        }

        return false;
    }
private function isNullIdentifier ( $ identifier ) { if ( null === $ identifier ) { return true ; } if ( $ identifier instanceof Traversable || is_array ( $ identifier ) ) { $ nonNullIdentifiers = array_filter ( ArrayUtils :: iteratorToArray ( $ identifier ) , function ( $ value ) { return null !== $ value ; } ) ; return empty ( $ nonNullIdentifiers ) ; } return false ; }
Verifies if a provided identifier is to be considered null

@param  mixed $identifier

@return bool
Verifies if a provided identifier is to be considered null