KeyError: key ***** [86cd37e6-c0ff-550b-95fe-21d72c8d4fc9] not found while calling "Serialization.deserialize(f)" function

Hi. I got a KeyError as the above when using the package *****. Could anyone please let me know what might be wrong?

Check that your module name in Package.jl is correctly named and capitalized.

Edit: Nvm, the original post got edited.

where to find the file Package.jl ?

I’m still confused though, what is exactly this “KeyError”? Why is the package name ever used as a key then? Could anyone explain it to me?