Use basestring instead of str to determine when to return headers as-is. This makes...

diff --git a/requests/compat.py b/requests/compat.py
index 00fbd2a13bd02082b46b386750db82b9e6fa37dd..fec7a01d7f4fb3ffa273ce251b3b7c30b47518d5 100644 (file)
--- a/requests/compat.py
+++ b/requests/compat.py
@@ -88,6 +88,7 @@ if is_py2:
 
     bytes = str
     str = unicode
+    basestring = basestring
 
 
 
@@ -100,4 +101,5 @@ elif is_py3:
 
     str = str
     bytes = bytes
+    basestring = (str,bytes)
 

diff --git a/requests/utils.py b/requests/utils.py
index 0e0f69ee879eaf7febdaf35a035d0f7b34e1654d..0f23a52790b532a837f289e8d1fe752ed6fdadc9 100644 (file)
--- a/requests/utils.py
+++ b/requests/utils.py
@@ -18,6 +18,7 @@ import zlib
 
 from .compat import parse_http_list as _parse_list_header
 from .compat import quote, unquote, cookielib, SimpleCookie, is_py2
+from .compat import basestring
 
 
 def dict_from_string(s):
@@ -146,7 +147,7 @@ def header_expand(headers):
     if isinstance(headers, dict):
         headers = list(headers.items())
 
-    elif isinstance(headers, str):
+    elif isinstance(headers, basestring):
         return headers
 
     for i, (value, params) in enumerate(headers):