value can't be text anymore
@@ -789,7 +789,7 @@ class ResponseBody(object):
if isinstance(value, six.text_type):
raise ValueError(self.unicode_err)
- if isinstance(value, text_or_bytes):
+ if isinstance(value, bytes):
# strings get wrapped in a list because iterating over a single
# item list is much faster than iterating over every character
# in a long string.
