Fix exception causes in server.py

cool-RR · cool-RR · commit 17a3c8c73417 · 2020-06-13T15:13:36.000+03:00
diff --git a/src/websockets/server.py b/src/websockets/server.py
@@ -340,8 +340,8 @@ def process_origin(
         # per https://tools.ietf.org/html/rfc6454#section-7.3.
         try:
             origin = cast(Origin, headers.get("Origin"))
-        except MultipleValuesError:
-            raise InvalidHeader("Origin", "more than one Origin header found")
+        except MultipleValuesError as e:
+            raise InvalidHeader("Origin", "more than one Origin header found") from e
         if origins is not None:
             if origin not in origins:
                 raise InvalidOrigin(origin)
