def _get_urls_to_load(ctx):
    """Build a dictionary of {url: sha} items that represent all urls to be downloaded"""
    all_urls = {}
    if ctx.attr.urls:
        all_urls.update(ctx.attr.urls)
    if ctx.attr.url:
        all_urls.update({ctx.attr.url: ctx.attr.sha256})
        all_urls.update(all_urls)
    return all_urls