* Maybe solve the none bug?
* cargo fmt
* use nothing, not string
* check at last
* I check it at last
* Use error which has span
* use not found error
* fix error
* use a empty value length?
* * Add commit about what I change and fmt
Now all test passed, but I do not know if it is right
* update the test
* check if it is nothing
* update commit
* Rename test
Co-authored-by: Jakub Žádník <kubouch@gmail.com>