diff --git a/paste/lint.py b/paste/lint.py
index d7816864..973132ad 100644
--- a/paste/lint.py
+++ b/paste/lint.py
@@ -217,7 +217,6 @@ def __init__(self, wsgi_errors):
         self.errors = wsgi_errors
 
     def write(self, s):
-        assert isinstance(s, bytes)
         self.errors.write(s)
 
     def flush(self):