From 1ab6a7d0d05a49cd84da3521756f1abe457b6aaa Mon Sep 17 00:00:00 2001
From: Matthew Harrigan <mpharrigan@google.com>
Date: Fri, 6 Oct 2023 10:44:57 -0700
Subject: [PATCH] Bugfix: fix final_soqs for LEFT bloqs

---
 qualtran/_infra/composite_bloq.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/qualtran/_infra/composite_bloq.py b/qualtran/_infra/composite_bloq.py
index 59db334ba..58cef8c7b 100644
--- a/qualtran/_infra/composite_bloq.py
+++ b/qualtran/_infra/composite_bloq.py
@@ -268,6 +268,8 @@ def final_soqs(self) -> Dict[str, SoquetT]:
 
         This method is helpful for finalizing an "add from" operation, see `iter_bloqsoqs`.
         """
+        if RightDangle not in self._binst_graph:
+            return {}
         final_preds, _ = _binst_to_cxns(RightDangle, binst_graph=self._binst_graph)
         return _cxn_to_soq_dict(
             self.signature.rights(),