diff --git a/Lib/urllib/request.py b/Lib/urllib/request.py
index 94b713e..fe2cfcd 100644
--- a/Lib/urllib/request.py
+++ b/Lib/urllib/request.py
@@ -1062,8 +1062,9 @@
         if request.data is not None:  # POST
             data = request.data
             if isinstance(data, str):
-                raise TypeError("POST data should be bytes"
-                        " or an iterable of bytes. It cannot be str.")
+                msg = "POST data should be bytes or an iterable of bytes."\
+                      "It cannot be str"
+                raise TypeError(msg)
             if not request.has_header('Content-type'):
                 request.add_unredirected_header(
                     'Content-type',