/** * Get ISBN-10 Registration Group Data by its numeric ID * * @param integer $id Registration Group Identifier * * @return mixed array: group array * boolean: False if failed */ function _getISBN10Group($id) { $r = settype($id, 'integer'); if ($r === false) { return false; } $groups = ISBN::_getISBN10Groups(); if ($groups === false) { return false; } if (isset($groups[$id]) === false) { return false; } $group = $groups[$id]; return $group; }