diff --git a/core/cat/looking_glass/cheshire_cat.py b/core/cat/looking_glass/cheshire_cat.py
index dd62d97e..f5ffa22d 100644
--- a/core/cat/looking_glass/cheshire_cat.py
+++ b/core/cat/looking_glass/cheshire_cat.py
@@ -300,7 +300,7 @@ def send_ws_message(self, content: str, msg_type: MSG_TYPES = "notification"):
         if msg_type not in options:
             raise ValueError(f"The message type `{msg_type}` is not valid. Valid types: {', '.join(options)}")
 
-        if msg_type is "error":
+        if msg_type == "error":
             self.ws_messages.append({
                 "type": msg_type,
                 "name": "GenericError",