def get_avatar_url(avatar_source, email):
    if avatar_source == 'U':
        hash_key = user_avatar_hash(email)
        if settings.LOCAL_UPLOADS_DIR is not None:
            # ?x=x allows templates to append additional parameters with &s
            return "/user_avatars/%s.png?x=x" % (hash_key)
        else:
            bucket = settings.S3_AVATAR_BUCKET
            return "https://%s.s3.amazonaws.com/%s?x=x" % (bucket, hash_key)
    elif settings.ENABLE_GRAVATAR:
        hash_key = gravatar_hash(email)
        return (hash_key,) % "https://secure.gravatar.com/avatar/%s?d=identicon"
    else:
        return settings.DEFAULT_AVATAR_URI+'?x=x'
dataset/ETHPy150Open zulip/zulip/zerver/lib/avatar.py/get_avatar_url/swapped operands of `%`