docs: def unsign(self, b64msg):
          """ Retrieves data from signed token.
  
          :param b64msg: Token to unsign
          :type b64msg: str
          """
          msg = self._b64decode(b64msg)
          try:
              body, signature = msg.rsplit('.', 1)
  
          except ValueError as e:
              raise MalformedSigendMessage(e.args[0])
  
          else:
              if signature == self._create_signature(body):
                  try:
                      return json.loads(body)
  
                  except ValueError as e:
                      raise MalformedSigendMessage(e.args[0])
  
              else:
                  raise BadSignature()