only import oauthlib in python2

diff --git a/requests/auth.py b/requests/auth.py
index 58e3206..2febe49 100644 (file)
--- a/requests/auth.py
+++ b/requests/auth.py
@@ -11,14 +11,16 @@ import time
 import hashlib
 
 from base64 import b64encode
-from oauthlib.oauth1.rfc5849 import (Client,
-                                     SIGNATURE_HMAC, SIGNATURE_TYPE_AUTH_HEADER)
+
 from oauthlib.common import extract_params
-from .compat import urlparse, str
+from .compat import urlparse, str, is_py2
 from .utils import randombytes, parse_dict_header
 
 CONTENT_TYPE_FORM_URLENCODED = 'application/x-www-form-urlencoded'
 
+if is_py2:
+    from oauthlib.oauth1.rfc5849 import (Client, SIGNATURE_HMAC, SIGNATURE_TYPE_AUTH_HEADER)
+
 def _basic_auth_str(username, password):
     """Returns a Basic Auth string."""