def METHOD_NAME(
    thumbnails: List[ResponsiveImageThumbnail], column_sizes: ColumnSizes
) -> ResponsiveImage:
    by_alias = {thumbnail.alias: thumbnail for thumbnail in thumbnails}
    extra_source_types = get_extra_source_types()
    original_mime_type = ""
    all_source_types = [
        ResponsiveImageSourceTypes(mime_type=original_mime_type, extension=""),
    ] + extra_source_types
    srcset = get_srcsets(all_source_types, thumbnails)
    img_sizes = get_imgsizes(column_sizes)
    sources = [
        ResponsiveImageSource(
            srcset=srcset[source_type.mime_type],
            mime_type=source_type.mime_type,
        )
        for source_type in extra_source_types
    ]
    src = by_alias.get(settings.THUMBNAIL_DEFAULT_ALIAS)
    if src is None:
        src = by_alias.get("original")
    if src:
        src = src.url
    else:
        src = ""
    return ResponsiveImage(
        src=src,
        srcset=srcset[original_mime_type],
        sizes=img_sizes,
        sources=sources,
    )