I have some error after installing plugin The reserved indicator "@" cannot start a plain scalar; you need to quote the scalar at line 6 (near "form: @/plugins/shahiemseymor/gallery/models/galleries/fields.yaml").

and // a non-quoted string cannot start with @ or (reserved) nor with a scalar indicator (| or >) if ($output && ('@' === $output[0] || '' === $output[0] || '|' === $output[0] || '>' === $output[0])) { throw new ParseException(sprintf('The reserved indicator "%s" cannot start a plain scalar; you need to quote the scalar.', $output[0]), self::$parsedLineNumber + 1, $output, self::$parsedFilename); }