Experimental calculator 1.0.0

Warning! Use this plugin at your own risk!
(Though it’s unlikely to cause issues, just a fair warning!)
I’m a beginner and noticed that there’s no such plugin for Nukkit, so I decided to make one. I take no responsibility for any problems caused by this plugin! I’m not obligated to provide fixes or updates.
As I mentioned, I’m still learning and may not write perfect code yet. But if you have suggestions, feel free to share them!
Caution: Possible bugs!
Command example: /calc 1 + 1 (I think you get the idea).
Permission: calc.use