def upload_file(s3_client, file_name, bucket, object_name=None):
    """Upload a file to an S3 bucket

    :param file_name: File to upload
    :param bucket: Bucket to upload to
    :param object_name: S3 object name. If not specified then file_name is used
    :return: True if file was uploaded, else False
    """
    # If S3 object_name was not specified, use file_name
    if object_name is None:
        object_name = file_name

    return s3_client.upload_file(file_name, bucket, object_name)