'Subclasses must override this to get basic information about the
user.
Should return a `.Future` whose result is a dictionary
containing information about the user, which may have been
retrieved by using ``access_token`` to make a request to the
service.
The access token will be added to the returned dictionary to make
the result of `get_authenticated_user`.
For backwards compatibility, the callback-based ``_oauth_get_user``
method is also supported.'

@return_future
def _oauth_get_user_future(self, access_token, callback):

    self._oauth_get_user(access_token, callback)
