def METHOD_NAME(tmpdir):
    with rasterio.open('tests/data/RGB.byte.tif') as src:
        profile = src.profile
        shadowed_profile = profile.copy()
        shadowed_profile['count'] = 4
        with rasterio.open(
                str(tmpdir.join('shadowed.tif')), 'w',
                **shadowed_profile) as dst:
            for i, band in enumerate(src.read(masked=False), 1):
                dst.write(band, i)
            dst.write(band, 4)
        del profile['nodata']
        with rasterio.open(
                str(tmpdir.join('no-nodata.tif')), 'w',
                **profile) as dst:
            dst.write(src.read(masked=False))
        with rasterio.open(
                str(tmpdir.join('sidecar-masked.tif')), 'w',
                **profile) as dst:
            dst.write(src.read(masked=False))
            mask = np.zeros(src.shape, dtype='uint8')
            dst.write_mask(mask)
    return tmpdir