I am getting this strange error when importing a module I wrote into my Dancer app.

```
Prototype mismatch: sub main::from_json: none vs ($@) at mymodule.pm line 6.
Prototype mismatch: sub main::to_json: none vs ($@) at mymodule.pm line 6.

```

I guess this is because in my module I'm importing the perl JSON module. 

Everything seems to perform fine, but I'm wondering what this error/warning is all about? I can't seem to find anything about it online.