Remove double isinstance check in force_unicode

                    # output should be.

                    s = ' '.join([force_unicode(arg, encoding, strings_only,

                            errors) for arg in s])

        elif not isinstance(s, six.text_type):

        else:

            # Note: We use .decode() here, instead of six.text_type(s, encoding,

            # errors), so that if s is a SafeString, it ends up being a

            # SafeUnicode at the end.