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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 _find_path(start, end, path=tuple()):
 """Return the path from start to end. If no path exists, return None. """

    path = path + (start, )
    if start is end:
        return path
    else:
        ret = None
        if start.lo is not None:
            ret = _find_path(start.lo, end, path)
        if ret is None and start.hi is not None:
            ret = _find_path(start.hi, end, path)
        return ret