docs: def is_token_valid(self, token):
          """
          Checks validity of a given token
  
          :param token: Access or refresh token
          """
  
          try:
              _tinfo = self.handler.info(token)
          except KeyError:
              return False
  
          if is_expired(int(_tinfo['exp'])) or _tinfo['black_listed']:
              return False
  
          # Dependent on what state the session is in.
          session_info = self[_tinfo['sid']]
  
          if session_info["oauth_state"] == "authz":
              if _tinfo['handler'] != self.handler['code']:
                  return False
          elif session_info["oauth_state"] == "token":
              if _tinfo['handler'] != self.handler['access_token']:
                  return False
  
          return True