def METHOD_NAME(self):
    """Creates a new Rocket Chat API client if needed and sets it as the client to use for requests.
    Returns newly created Rocket Chat API client, or current client if already set.
    """
    if self.is_connected and self.client is not None:
        return self.client
    self.client = RocketChat(
        user=self.username,
        password=self.password,
        auth_token=self.auth_token,
        user_id=self.auth_user_id,
        server_url=self.domain
    )
    self.is_connected = True
    return self.client