From 61ac5850db0ad3fc364d33d0d73ba2242a7d9958 Mon Sep 17 00:00:00 2001
From: Razin Shaikh <razinshaikh@outlook.com>
Date: Wed, 26 Jun 2024 18:49:41 +0100
Subject: [PATCH] self loop support: avoid deleting self edges twice

---
 pyzx/graph/multigraph.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pyzx/graph/multigraph.py b/pyzx/graph/multigraph.py
index f2d2a858..66407ae7 100644
--- a/pyzx/graph/multigraph.py
+++ b/pyzx/graph/multigraph.py
@@ -244,7 +244,7 @@ def remove_edge(self, edge):
 
         if e.is_empty():
             del self.graph[s][t]
-            del self.graph[t][s]
+            if s != t: del self.graph[t][s]
 
         self.nedges -= 1