diff --git a/gap/classes.gi b/gap/classes.gi
index 7a42fc0..8712731 100644
--- a/gap/classes.gi
+++ b/gap/classes.gi
@@ -38,7 +38,7 @@ InstallTrueMethod( IsExtraLoop, IsAssociative and IsLoop );
 ##
 ##  Returns true if <Q> is commutative.
 
-InstallOtherMethod( IsCommutative, "for quasigroup",
+InstallMethod( IsCommutative, "for quasigroup",
     [ IsQuasigroup ],
 function( Q )
     return LeftSection( Q ) = RightSection( Q );