diff --git a/src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_net_command.py b/src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_net_command.py
index 4ca2e0c8..eeacbb3d 100644
--- a/src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_net_command.py
+++ b/src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_net_command.py
@@ -80,7 +80,7 @@ class NetCommand(_BaseNetCommand):
             try:
                 text = json.dumps(as_dict)
             except TypeError:
-                text = json.dumps(as_dict, default=lambda o: str(o))
+                text = json.dumps(as_dict, default=str)
 
         assert isinstance(text, str)