def METHOD_NAME(app_, mocker):
    mocked_s3_upload = mocker.patch("app.s3_client.s3_logo_client.utils_s3upload")
    with app_.app_context():
        mocker.patch.dict("flask.current_app.config", {"LOGO_UPLOAD_BUCKET_NAME": bucket})
    upload_letter_png_logo(filename, data, region)
    mocked_s3_upload.assert_called_once_with(
        filedata=data,
        region=region,
        bucket_name=bucket,
        file_location=filename,
        content_type="image/png",
    )