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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 preauthChild(self, path):
 """ Use me if `path' might have slashes in it, but you know they're safe. (NOT slashes at the beginning. It still needs to be a _child_). """

        newpath = abspath(joinpath(self.path, normpath(path)))
        if not newpath.startswith(self.path):
            raise InsecurePath("%s is not a child of %s" % (newpath, self.path))
        return self.clonePath(newpath)