if self.auto_error:
                raise self.make_not_authenticated_error()
            else:
                return None
        return param


class OAuth2AuthorizationCodeBearer(OAuth2):
    """
    OAuth2 flow for authentication using a bearer token obtained with an OAuth2 code
    flow. An instance of it would be used as a dependency.
    """

    def __init__(

* Add link to Chinese article in [External Links](https://fastapi.tiangolo.com/external-links/). PR [810](https://github.com/tiangolo/fastapi/pull/810) by [@wxq0309](https://github.com/wxq0309).
* Implement `OAuth2AuthorizationCodeBearer` class. PR [#797](https://github.com/tiangolo/fastapi/pull/797) by [@kuwv](https://github.com/kuwv).