diff --git a/eventlet/support/__init__.py b/eventlet/support/__init__.py
index b311c8a..0970f31 100644
--- a/eventlet/support/__init__.py
+++ b/eventlet/support/__init__.py
@@ -73,8 +73,10 @@ Autoupgrade: fgrep -rl '{old}' . |xargs -t sed --in-place='' -e 's/{old}/{new}/'
     def wrapper(base):
         klass = None
         if inspect.isclass(base):
-            klass = base
-            base = klass.__init__
+            class klass(base):
+                pass
+            klass.__name__ = base.__name__
+            klass.__module__ = base.__module__
 
         @functools.wraps(base)
         def wrapped(*a, **kw):
diff --git a/tests/api_test.py b/tests/api_test.py
index 2b2e93f..3ebc67c 100644
--- a/tests/api_test.py
+++ b/tests/api_test.py
@@ -177,3 +177,10 @@ def test_wrap_is_timeout():
 
     obj = eventlet.wrap_is_timeout(A)()
     tests.check_is_timeout(obj)
+
+
+def test_timeouterror_deprecated():
+    # https://github.com/eventlet/eventlet/issues/378
+    code = '''import eventlet; eventlet.Timeout(1).cancel(); print('pass')'''
+    args = ['-Werror:eventlet.Timeout:DeprecationWarning', '-c', code]
+    tests.run_python(path=None, args=args, expect_pass=True)