def get_player_achievements(self, steamID, appID, language=None,
            format=None):
        """Request the achievements for a given app and steam id.

        steamID: Users steam ID
        appID: The app id
        language: The language to return the results in. None uses default.
        format: Return format. None defaults to json. (json, xml, vdf)

        """
        parameters = {'steamid' : steamID, 'appid' : appID}
        if format is not None:
            parameters['format'] = format
        if language is not None:
            parameters['l'] = language
        else:
            parameters['l'] = self.language
        url = self.create_request_url(self.interface, 'GetPlayerAchievements', 1,
            parameters)
        data = self.retrieve_request(url)
        return self.return_data(data, format=format)
Request the achievements for a given app and steam id.

        steamID: Users steam ID
        appID: The app id
        language: The language to return the results in. None uses default.
        format: Return format. None defaults to json. (json, xml, vdf)