private function getFieldKey(array $requestedFields = null): string
    {
        if (is_null($requestedFields)) {
            return 'no-field-key';
        }
        return $fieldKey = '.' . sha1(implode(',', $requestedFields));
    }
private function getFieldKey(array $requestedFields = null): string
    {
        if (is_null($requestedFields)) {
            return 'no-field-key';
        }
        return $fieldKey = '.' . sha1(implode(',', $requestedFields));
    }
private function getFieldKey ( array $ requestedFields = null ) : string { if ( is_null ( $ requestedFields ) ) { return 'no-field-key' ; } return $ fieldKey = '.' . sha1 ( implode ( ',' , $ requestedFields ) ) ; }
A lot of calls contain the fields one want's to have in return.
Make sure this is also added to the item key.

@param array $requestedFields
@return string
A lot of calls contain the fields one want s to have in return . Make sure this is also added to the item key .