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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def findall(dir=os.curdir):
 """ Find all files under 'dir' and return the list of full filenames. Unless dir is '.', return full filenames with dir prepended. """

    files = _find_all_simple(dir)
    if dir == os.curdir:
        make_rel = functools.partial(os.path.relpath, start=dir)
        files = map(make_rel, files)
    return list(files)