diff --git a/falcon/response.py b/falcon/response.py
index affd036..b5d1b2a 100644
--- a/falcon/response.py
+++ b/falcon/response.py
@@ -146,7 +146,7 @@ class Response(object):
         self.stream_len = stream_len
 
     def set_cookie(self, name, value, expires=None, max_age=None,
-                   domain=None, path=None, secure=True, httponly=True):
+                   domain=None, path=None, secure=True, http_only=True):
         """Set a response cookie.
 
         Note:
@@ -177,8 +177,8 @@ class Response(object):
                 server whenever it sends back this cookie.
                 Warning: You will also need to enforce HTTPS for the cookies
                 to be transfered securely.
-            httponly (bool) (default: True):
-                The attribute httponly specifies that the cookie
+            http_only (bool) (default: True):
+                The attribute http_only specifies that the cookie
                 is  only transferred in HTTP requests, and is not accessible
                 through JavaScript. This is intended to mitigate some forms
                 of cross-site scripting.
@@ -241,8 +241,8 @@ class Response(object):
         if secure:
             self._cookies[name]["secure"] = secure
 
-        if httponly:
-            self._cookies[name]["httponly"] = httponly
+        if http_only:
+            self._cookies[name]["httponly"] = http_only
 
     def unset_cookie(self, name):
         """Unset a cookie from the response
diff --git a/falcon/response_helpers.py b/falcon/response_helpers.py
index 84f778e..fd09504 100644
--- a/falcon/response_helpers.py
+++ b/falcon/response_helpers.py
@@ -11,7 +11,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import six
 
 
 def header_property(name, doc, transform=None):
@@ -64,15 +63,18 @@ def format_range(value):
 
 
 def is_ascii_encodable(s):  # pragma: no cover
-    """ check if argument encodes to ascii without error
-    """
-    if isinstance(s, six.text_type):
-        try:
-            s.encode("ascii")
-            return True
-        except UnicodeEncodeError:
-            return False
-    elif six.PY2 and isinstance(s, str):
-        return True
-    else:
-        raise ValueError("argument was not a string type")
+    """Check if argument encodes to ascii without error."""
+    try:
+        s.encode("ascii")
+    except UnicodeEncodeError:
+        # NOTE(tbug): Py2 and Py3 will raise this if string contained
+        # chars that could not be ascii encoded
+        return False
+    except UnicodeDecodeError:
+        # NOTE(tbug): py2 will raise this if type is str
+        # and contains non-ascii chars
+        return False
+    except AttributeError:
+        # NOTE(tbug): s is probably not a string type
+        return False
+    return True
diff --git a/tests/test_cookies.py b/tests/test_cookies.py
index ae4fe2d..e98d666 100644
--- a/tests/test_cookies.py
+++ b/tests/test_cookies.py
@@ -29,18 +29,18 @@ class CookieResource:
 
     def on_head(self, req, resp):
         resp.set_cookie("foo", "bar", max_age=300)
-        resp.set_cookie("bar", "baz", httponly=False)
+        resp.set_cookie("bar", "baz", http_only=False)
         resp.set_cookie("bad", "cookie")
         resp.unset_cookie("bad")
 
     def on_post(self, req, resp):
         e = datetime(year=2050, month=1, day=1)  # naive
-        resp.set_cookie("foo", "bar", httponly=False, secure=False, expires=e)
+        resp.set_cookie("foo", "bar", http_only=False, secure=False, expires=e)
         resp.unset_cookie("bad")
 
     def on_put(self, req, resp):
         e = datetime(year=2050, month=1, day=1, tzinfo=GMT_PLUS_ONE)  # aware
-        resp.set_cookie("foo", "bar", httponly=False, secure=False, expires=e)
+        resp.set_cookie("foo", "bar", http_only=False, secure=False, expires=e)
         resp.unset_cookie("bad")