fixed whitespaces, prevent failing of other doctests

Author: AdityaK1729

src/sage/groups/perm_gps/permgroup.py

@@ -3306,15 +3306,15 @@ def commutator(self, other=None):
             TypeError: junk is not a permutation group
 
         TESTS:
-            
+
         Verify that :issue`39416` is fixed::
 
-            sage: G = PermutationGroup(gens=[("a", "b"), ("b","c")])
+            sage: G = PermutationGroup(gens=[(1,2), (2,4)], domain={1, 2, 4})
             sage: G.commutator()
-            Subgroup generated by [('a','b','c')] of (Permutation Group with generators [('b','c'), ('a','b')])
+            Permutation Group with generators [(1,2,4)]
         """
         if other is None:
-            return self.subgroup(gap_group=libgap.DerivedSubgroup(self))
+            return PermutationGroup(gap_group=libgap.DerivedSubgroup(self), domain=self.domain())
         else:
             from sage.categories.finite_permutation_groups import FinitePermutationGroups
             if other not in FinitePermutationGroups():