From 52d8b7f0d3e8a1c0d0dcef7a97c46374f230dc0c Mon Sep 17 00:00:00 2001
From: Jason Barnett <J@sonBarnett.com>
Date: Wed, 10 Jul 2024 17:59:40 -0600
Subject: [PATCH] fix azure service bus isinstance check (#2053)

---
 kombu/transport/azureservicebus.py | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/kombu/transport/azureservicebus.py b/kombu/transport/azureservicebus.py
index 35e689d2e..2a899027f 100644
--- a/kombu/transport/azureservicebus.py
+++ b/kombu/transport/azureservicebus.py
@@ -141,8 +141,13 @@ def _try_parse_connection_string(self) -> None:
         self._namespace, self._credential = Transport.parse_uri(
             self.conninfo.hostname)
 
-        if (isinstance(self._credential, DefaultAzureCredential) or
-                isinstance(self._credential, ManagedIdentityCredential)):
+        if (
+            DefaultAzureCredential is not None
+            and isinstance(self._credential, DefaultAzureCredential)
+        ) or (
+            ManagedIdentityCredential is not None
+            and isinstance(self._credential, ManagedIdentityCredential)
+        ):
             return None
 
         if ":" in self._credential: