Error "9" when function called

Hello everybody !
I'm trying to make a program that will show the energy in 4 draconic core via the rednet API
I write some function for put in form the variable but when I run the program, it return me just "9" in red.
I try to search for a similar error but I can't find any.
Do you already had an error like this ?

I vaguely remember seeing something about this once, but I can't find the reference right now.
I think this has something to do with another mod not handling errors properly when invalid arguments are passed to peripheral methods or something similar.
Edit: I've been over to Draconic Evolution's github and they're redistributing the computercraft API files which isn't something you are supposed to do. So it's probably their fault you're getting a noninformative error message. If you can narrow this down to a bad peripheral call I can probably submit a decent bug report, if not a PR to fix this. To be clear, your program is doing something wrong, but the mod isn't handling that correctly.

I just read a post here : https://github.com/b...tion/issues/125
It says (at the end) that the name of the peripheral is "draconic_rf_storage"
I'll try this tomorrow