Solver: Mage: Minor change.

src/Solver/Mage.py

@@ -322,6 +322,9 @@ class Mage(CommandLineSolver):
 
     @timer
     def _export_LC(self, study, lateral, f, qlog, name="0"):
+        if lateral.edge is None:
+            return
+
         edges = study.river.enable_edges()
         if lateral.edge not in edges:
             return