Does using a package of Affero GPL license in a large app mean the entire app has to be GNU?

I can’t figure out if Affero GPL only applies to any modifications made of the Affero GPL licensed software or ALL software that touches ANY Affero GPL software.

For example: I have a SaaS app where server side I have a function that responds to customer input, and modifies customer input using a Affero GPL licensed package.

from gplPackage import gpl  def myFunction(x):     x = x + 1     x = gpl(x)     return x 

So myFunction, which I wrote, calls a Affero GPL licensed function. Does this mean I have to release myFunction to the public under a Affero GPL license? Or would I only have to give away / give people the code for gplPackage?

I would like to use a Affero GPL licensed package in my app, but do not want to make my entire application, even stuff that I wrote myself, public.