def METHOD_NAME():
    client = boto3.client("polly", region_name=DEFAULT_REGION)
    resp = client.describe_voices()
    assert len(resp["Voices"]) >= 1
    resp = client.describe_voices(LanguageCode="en-GB")
    assert len(resp["Voices"]) == 4
    try:
        client.describe_voices(LanguageCode="SOME_LANGUAGE")
    except ClientError as err:
        assert err.response["Error"]["Code"] == "400"
    else:
        raise RuntimeError("Should have raised an exception")