diff --git a/pyTigerGraph/schema.py b/pyTigerGraph/schema.py
index 19750998..d9de9445 100644
--- a/pyTigerGraph/schema.py
+++ b/pyTigerGraph/schema.py
@@ -526,7 +526,7 @@ def add_edge_type(self, edge: Edge):
       
         if not(reverse_edge) and is_directed:
             raise TigerGraphException("Reverse edge definition not set. Set the reverse_edge variable to a boolean or string.")
-        if not(is_directed):
+        if is_directed is None:
             raise TigerGraphConnection("is_directed variable not defined. Define is_directed as a class variable to the desired setting.")
         
         if not(edge.attributes.get("from_vertex", None)):