Trac #34872: AdditiveAbelianGroup_class.exponent() returns a Python i…

…nt for the trivial group

{{{#!sage
sage: type(AdditiveAbelianGroup([]).exponent())
<class 'int'>
}}}

URL: https://trac.sagemath.org/34872
Reported by: lorenz
Ticket author(s): Lorenz Panny
Reviewer(s): Matthias Koeppe

src/sage/groups/additive_abelian/additive_abelian_group.py

@@ -352,7 +352,7 @@ def exponent(self):
             1
         """
         if not self.invariants():
-            return 1
+            return ZZ(1)
         else:
             ann =  self.annihilator().gen()
             if ann: