@classmethod
    def unserialize(cls, string, secret_key):
        """Load the secure cookie from a serialized string.

        :param string: the cookie value to unserialize.
        :param secret_key: the secret key used to serialize the cookie.
        :return: a new :class:`SecureCookie`.
        """
        if isinstance(string, text_type):
            string = string.encode('utf-8', 'replace')
        if isinstance(secret_key, text_type):
            secret_key = secret_key.encode('utf-8', 'replace')
        try:
            base64_hash, data = string.split(b'?', 1)
        except (__HOLE__, IndexError):
            items = ()
        else:
            items = {}
            mac = hmac(secret_key, None, cls.hash_method)
            for item in data.split(b'&'):
                mac.update(b'|' + item)
                if b'=' not in item:
                    items = None
                    break
                key, value = item.split(b'=', 1)
                # try to make the key a string
                key = url_unquote_plus(key.decode('ascii'))
                try:
                    key = to_native(key)
                except UnicodeError:
                    pass
                items[key] = value

            # no parsing error and the mac looks okay, we can now
            # sercurely unpickle our cookie.
            try:
                client_hash = base64.b64decode(base64_hash)
            except TypeError:
                items = client_hash = None
            if items is not None and safe_str_cmp(client_hash, mac.digest()):
                try:
                    for key, value in iteritems(items):
                        items[key] = cls.unquote(value)
                except UnquoteError:
                    items = ()
                else:
                    if '_expires' in items:
                        if time() > items['_expires']:
                            items = ()
                        else:
                            del items['_expires']
            else:
                items = ()
        return cls(items, secret_key, False)
dataset/ETHPy150Open GoogleCloudPlatform/appengine-flask-skeleton/lib/werkzeug/contrib/securecookie.py/SecureCookie.unserialize