Fix the wrong urllib exampls which use str for POST data. Closes Issue11261

Doc/howto/urllib2.rst

@@ -108,6 +108,7 @@ library. ::
               'language' : 'Python' }
 
     data = urllib.parse.urlencode(values)
+    data = data.encode('utf-8') # data should be bytes
     req = urllib.request.Request(url, data)
     response = urllib.request.urlopen(req)
     the_page = response.read()
@@ -173,6 +174,7 @@ Explorer [#]_. ::
     headers = { 'User-Agent' : user_agent }
 
     data  = urllib.parse.urlencode(values)
+    data = data.encode('utf-8')
     req = urllib.request.Request(url, data, headers)
     response = urllib.request.urlopen(req)
     the_page = response.read()

Doc/library/urllib.request.rst

@@ -138,14 +138,13 @@ The following classes are provided:
 
    *url* should be a string containing a valid URL.
 
-   *data* may be a string specifying additional data to send to the
-   server, or ``None`` if no such data is needed.  Currently HTTP
-   requests are the only ones that use *data*; the HTTP request will
-   be a POST instead of a GET when the *data* parameter is provided.
-   *data* should be a buffer in the standard
-   :mimetype:`application/x-www-form-urlencoded` format.  The
-   :func:`urllib.parse.urlencode` function takes a mapping or sequence
-   of 2-tuples and returns a string in this format.
+   *data* may be a bytes object specifying additional data to send to the
+   server, or ``None`` if no such data is needed.  Currently HTTP requests are
+   the only ones that use *data*; the HTTP request will be a POST instead of a
+   GET when the *data* parameter is provided.  *data* should be a buffer in the
+   standard :mimetype:`application/x-www-form-urlencoded` format.  The
+   :func:`urllib.parse.urlencode` function takes a mapping or sequence of
+   2-tuples and returns a string in this format.
 
    *headers* should be a dictionary, and will be treated as if
    :meth:`add_header` was called with each key and value as arguments.
@@ -1122,10 +1121,10 @@ some point in the future.
    size in response to a retrieval request.
 
    If the *url* uses the :file:`http:` scheme identifier, the optional *data*
-   argument may be given to specify a ``POST`` request (normally the request type
-   is ``GET``).  The *data* argument must in standard
-   :mimetype:`application/x-www-form-urlencoded` format; see the :func:`urlencode`
-   function below.
+   argument may be given to specify a ``POST`` request (normally the request
+   type is ``GET``).  The *data* argument must be a bytes object in standard
+   :mimetype:`application/x-www-form-urlencoded` format; see the
+   :func:`urlencode` function below.
 
    :func:`urlretrieve` will raise :exc:`ContentTooShortError` when it detects that
    the amount of data available  was less than the expected amount (which is the