diff --git a/ipranges.py b/ipranges.py
index 722436352cb97ea96653944889d3f6a316d0c2ae..3c8e61ed90de5b8b391d16f406d1858233009ee9 100644
--- a/ipranges.py
+++ b/ipranges.py
@@ -31,7 +31,7 @@ class Range(object):
             and hasattr(other, "single")
             and (
                 issubclass(self.single, other.single)
-                or issubclass(self.single, other.single)
+                or issubclass(other.single, self.single)
             )
         ):
             return self.low() == other.low() and self.high() == other.high()