def METHOD_NAME(sha1sumfile, root):
    needs_updating = []
    with open(sha1sumfile) as f:
        lines = f.readlines()
        for line in lines:
            line = line.split()
            sha1sum, filename = line
            fpath = os.path.join(root, filename)
            if os.path.isfile(fpath):
                if sha1sum != filehash(fpath):
                    needs_updating.append(filename)
            else:
                needs_updating.append(filename)
    return needs_updating