def METHOD_NAME():
    bucket_name = "mybucket"
    s3_client = boto3.client("s3", region_name="us-east-1")
    s3_client.create_bucket(Bucket=bucket_name)
    s3_client.put_object(Bucket=bucket_name, Key="/a/test.txt", Body="test")
    assert check_s3_object_exists(s3_client, bucket_name, "/a/test.txt") is True
    assert check_s3_object_exists(s3_client, bucket_name, "/a/test2.txt") is False