How to use the webob.compat.bytes_ function in WebOb

def serialize(secret, salt, data):
    import hmac
    import base64
    import json
    from hashlib import sha1
    from webob.compat import bytes_
    salted_secret = bytes_(salt or '', 'utf-8') + bytes_(secret, 'utf-8')
    cstruct = bytes_(json.dumps(data))
    sig = hmac.new(salted_secret, cstruct, sha1).digest()
    return base64.urlsafe_b64encode(sig + cstruct).rstrip(b'=')

# end of headers
                break
            hname, hval = line.split(colon, 1)
            hname = native_(hname, 'utf-8')
            hval = native_(hval, 'utf-8').strip()
            if hname in r.headers:
                hval = r.headers[hname] + ', ' + hval
            r.headers[hname] = hval
        if r.method in ('PUT', 'POST'):
            clen = r.content_length
            if clen is None:
                body = fp.read()
            else:
                body = fp.read(clen)
            if is_text:
                body = bytes_(body, 'utf-8')
            r.body = body
        return r

def encset(self, key, val, encattr=None):
        if encattr:
            encoding = getattr(self, encattr)
        else:
            encoding = 'ascii'
        if PY3: # pragma: no cover
            self.environ[key] = bytes_(val, encoding).decode('latin-1')
        else:
            self.environ[key] = bytes_(val, encoding)

"""Like wsgiref.url.request_uri, except eliminates :80 ports

    Return the full request URI"""
    url = environ['wsgi.url_scheme']+'://'

    if environ.get('HTTP_HOST'):
        url += environ['HTTP_HOST']
    else:
        url += environ['SERVER_NAME'] + ':' + environ['SERVER_PORT']
    if url.endswith(':80') and environ['wsgi.url_scheme'] == 'http':
        url = url[:-3]
    elif url.endswith(':443') and environ['wsgi.url_scheme'] == 'https':
        url = url[:-4]

    if PY3: # pragma: no cover
        script_name = bytes_(environ.get('SCRIPT_NAME', '/'), 'latin-1')
        path_info = bytes_(environ.get('PATH_INFO', ''), 'latin-1')
    else:
        script_name = environ.get('SCRIPT_NAME', '/')
        path_info = environ.get('PATH_INFO', '')

    url += url_quote(script_name)
    qpath_info = url_quote(path_info)
    if not 'SCRIPT_NAME' in environ:
        url += qpath_info[1:]
    else:
        url += qpath_info
    return url

"""
        if overwrite:
            self.unset_cookie(key, strict=False)
        if value is None: # delete the cookie from the client
            value = ''
            max_age = 0
            expires = timedelta(days=-5)
        elif expires is None and max_age is not None:
            if isinstance(max_age, int):
                max_age = timedelta(seconds=max_age)
            expires = datetime.utcnow() + max_age
        elif max_age is None and expires is not None:
            max_age = expires - datetime.utcnow()
        value = bytes_(value, 'utf8')
        key = bytes_(key, 'utf8')
        m = Morsel(key, value)
        m.path = bytes_(path, 'utf8')
        m.domain = bytes_(domain, 'utf8')
        m.comment = bytes_(comment, 'utf8')
        m.expires = expires
        m.max_age = max_age
        m.secure = secure
        m.httponly = httponly
        self.headerlist.append(('Set-Cookie', m.serialize()))

def encset(self, key, val, encattr=None):
        if encattr:
            encoding = getattr(self, encattr)
        else:
            encoding = 'ascii'
        if PY3: # pragma: no cover
            self.environ[key] = bytes_(val, encoding).decode('latin-1')
        else:
            self.environ[key] = bytes_(val, encoding)

max_age = (max_age.days * 60 * 60 * 24) + max_age.seconds
        expires = max_age
    elif max_age is not None:
        try:
            max_age = int(max_age)
        except ValueError:
            raise ValueError('max_age should be an integer. Amount of seconds until expiration.')

        expires = max_age
    else:
        expires = None

    morsel = Morsel(name, value)

    if domain is not None:
        morsel.domain = bytes_(domain)
    if path is not None:
        morsel.path = bytes_(path)
    if httponly:
        morsel.httponly = True
    if secure:
        morsel.secure = True
    if max_age is not None:
        morsel.max_age = max_age
    if expires is not None:
        morsel.expires = expires
    if comment is not None:
        morsel.comment = bytes_(comment)
    return morsel.serialize()

elif max_age is not None:
        try:
            max_age = int(max_age)
        except ValueError:
            raise ValueError('max_age should be an integer. Amount of seconds until expiration.')

        expires = max_age
    else:
        expires = None

    morsel = Morsel(name, value)

    if domain is not None:
        morsel.domain = bytes_(domain)
    if path is not None:
        morsel.path = bytes_(path)
    if httponly:
        morsel.httponly = True
    if secure:
        morsel.secure = True
    if max_age is not None:
        morsel.max_age = max_age
    if expires is not None:
        morsel.expires = expires
    if comment is not None:
        morsel.comment = bytes_(comment)
    return morsel.serialize()

status304 = self.last_modified <= req.if_modified_since
            if status304:
                start_response("304 Not Modified", filter_headers(headerlist))
                return EmptyResponse(self._app_iter)
        if (
            req.range
            and self in req.if_range
            and self.content_range is None
            and method in ("HEAD", "GET")
            and self.status_code == 200
            and self.content_length is not None
        ):
            content_range = req.range.content_range(self.content_length)
            if content_range is None:
                iter_close(self._app_iter)
                body = bytes_("Requested range not satisfiable: %s" % req.range)
                headerlist = [
                    ("Content-Length", str(len(body))),
                    (
                        "Content-Range",
                        str(ContentRange(None, None, self.content_length)),
                    ),
                    ("Content-Type", "text/plain"),
                ] + filter_headers(headerlist)
                start_response("416 Requested Range Not Satisfiable", headerlist)
                if method == "HEAD":
                    return ()
                return [body]
            else:
                app_iter = self.app_iter_range(content_range.start, content_range.stop)
                if app_iter is not None:
                    # the following should be guaranteed by

def loads(self, bstruct):
        """
        Given a ``bstruct`` (a bytestring), verify the signature and then
        deserialize and return the deserialized value.

        A ``ValueError`` will be raised if the signature fails to validate.
        """
        try:
            cstruct = base64.urlsafe_b64decode(bytes_(bstruct))
        except (binascii.Error, TypeError) as e:
            raise ValueError('Badly formed base64 data: %s' % e)

        return self.serializer.loads(cstruct)