diff --git a/peps/pep-3333.rst b/peps/pep-3333.rst
index 4ec70d84f..1803b28b9 100644
--- a/peps/pep-3333.rst
+++ b/peps/pep-3333.rst
@@ -348,7 +348,7 @@ server.
                 if data:    # don't send headers until body appears
                     write(data)
             if not headers_sent:
-                write('')   # send headers now if body was empty
+                write(b'')   # send headers now if body was empty
         finally:
             if hasattr(result, 'close'):
                 result.close()