Ember addon. method findBy() is not a function

I'm building an Ember addon using an Ember app that I've already built, but I'm having an issue with the method .findBy().

Basically in the app .findBy() works for an array of Objects (ember.Array class), but if I try to use it in the addon I get:

selectorsData.findBy() is not a function(...)

I think that the Addon doesn't recognize that it is an ember.Array

Picture of the methods for the array of objects IN THE ADDON

Picture of the methods for the array of objects IN THE EMBER APP