docs: def login_required(self, f):
          """
          Require a user to be validated by Identity to access an endpoint.
  
          :raises: FlaskKeystoneUnauthorized
  
          This method will gate a particular endpoint to only be accessed by
          :class:`FlaskKeystone.User`'s. This means that a valid token will need
          to be passed to grant access. If a User is not authenticated,
          a FlaskKeystoneUnauthorized will be thrown, resulting in a 401 response
          to the client.
          """
          @wraps(f)
          def wrapped_f(*args, **kwargs):
              if current_user.anonymous:
                  msg = ("Rejected User '%s access to '%s' as user"
                         " could not be authenticated.")
                  self.logger.warn(msg % (
                      current_user.user_id,
                      request.path
                  ))
                  raise FlaskKeystoneUnauthorized()
              return f(*args, **kwargs)
          return wrapped_f