code: def get_user_by_auth_token(token=None):
      
      if not token:
          token = request.get_auth_token()
      secret_key = get_jwt_secret()
      s = utils.unsign_jwt(token=token,
                           secret_key=secret_key,
                           salt=get_jwt_salt())
      if "id" not in s:
          raise exceptions.AuthError("Invalid Authorization Bearer Token")
      return get_user_by_id(int(s["id"]))
docs: Return the AuthUser associated to the token, otherwise it will return None.
      If token is not provided, it will pull it from the headers: Authorization
  
      Exception:
      Along with AuthError, it may
      :param token:
      :return: AuthUser