diff --git a/causallearn/graph/Endpoint.py b/causallearn/graph/Endpoint.py
index df551955..83f1ece4 100644
--- a/causallearn/graph/Endpoint.py
+++ b/causallearn/graph/Endpoint.py
@@ -20,4 +20,4 @@ def __str__(self):
         return self.name
 
     def __eq__(self, other):
-        return self.value == other.value
+        return isinstance(other, Endpoint) and self.value == other.value