diff --git a/example.py b/example.py
index bf28aa1..192fbf9 100644
--- a/example.py
+++ b/example.py
@@ -16,10 +16,10 @@
                 redirect_uri=REDIRECT_URI)
 
 try:
-    print api.get_authorize_login_url(scope=("snsapi_login",))
-    print api.exchange_code_for_access_token(code=code)
-except OAuth2AuthExchangeError, e:
-    print e
+    print(api.get_authorize_login_url(scope=("snsapi_login",)))
+    print(api.exchange_code_for_access_token(code=code))
+except OAuth2AuthExchangeError as e:
+    print(e)
 
 auth_info = {
     'access_token': 'OezXcEiiBSKSxW0eoylIeGXVgVFIUy2pK5I7TVatC5MGtVqTIWjtyV5Pax8ZLiWw-NdEN9dPkEX8Yewsve2AktmzS0gmbvzRKO49l6sxHRfhXg1no5ObdGufYhRIubP2m3FUdv-Cop3t3S_xwMbBWQ',
@@ -28,11 +28,11 @@
     'expires_in': 7200,
     'scope': u'snsapi_login'}
 
-print api.exchange_refresh_token_for_access_token(refresh_token=auth_info['refresh_token'])
+print(api.exchange_refresh_token_for_access_token(refresh_token=auth_info['refresh_token']))
 
 api = WeixinAPI(access_token=auth_info['access_token'])
 
 r = api.user(openid=auth_info['openid'])
-print r
+print(r)
 v = api.validate_token(openid=auth_info['openid'])
-print v
+print(v)
diff --git a/setup.py b/setup.py
index ac57b76..a1d4c6c 100644
--- a/setup.py
+++ b/setup.py
@@ -10,7 +10,7 @@
     requirements = [l for l in f.read().splitlines() if l]
 
 setup(name="python-weixin",
-      version="0.4.5",
+      version="0.4.6",
       description="Python Weixin API client support wechat-app",
       long_description=long_description,
       long_description_content_type="text/markdown",
diff --git a/weixin/helper.py b/weixin/helper.py
index 5cba964..995b8ba 100644
--- a/weixin/helper.py
+++ b/weixin/helper.py
@@ -295,7 +295,8 @@ def url_quote(string, charset='utf-8', errors='strict', safe='/:', unsafe=''):
         safe = safe.encode(charset, errors)
     if isinstance(unsafe, text_type):
         unsafe = unsafe.encode(charset, errors)
-    safe = frozenset(bytearray(safe) + _always_safe) - frozenset(bytearray(unsafe))
+    always_safe = _always_safe.encode(charset, errors)
+    safe = frozenset(bytearray(safe) + always_safe) - frozenset(bytearray(unsafe))
     rv = bytearray()
     for char in bytearray(string):
         if char in safe: