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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 _relative(self, uri):
 """ if uri is relative, re-relate it to our basedir """


        if uri.startswith("http:") or \
           uri.startswith("https:") or \
           uri.startswith("file:") or \
           uri.startswith("/"):
            return uri

        elif exists(uri):
            return relpath(uri, self.basedir)

        else:
            return uri