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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 replace_file_or_dir(dest, source):
 """Replace `dest` with `source`. Acts like an `os.rename` if `dest` does not exist. Otherwise, `dest` is deleted and `src` is renamed to `dest`. """

    from rez.vendor.atomicwrites import replace_atomic

    if not os.path.exists(dest):
        try:
            os.rename(source, dest)
            return
        except:
            if not os.path.exists(dest):
                raise

    try:
        replace_atomic(source, dest)
        return
    except:
        pass

    with make_tmp_name(dest) as tmp_dest:
        os.rename(dest, tmp_dest)
        os.rename(source, dest)