Returns all the key/secret settings for Twitter access,
    only if they're all defined.

def get_auth_settings():
    """
    Returns all the key/secret settings for Twitter access,
    only if they're all defined.
    """
    from yacms.conf import settings
    try:
        auth_settings = (settings.TWITTER_CONSUMER_KEY,
                         settings.TWITTER_CONSUMER_SECRET,
                         settings.TWITTER_ACCESS_TOKEN_KEY,
                         settings.TWITTER_ACCESS_TOKEN_SECRET)
    except AttributeError:
        return None
    else:
        return auth_settings if all(auth_settings) else None