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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 _uri_to_etext(cls, uri_ref):
 """Converts the representation used to identify a text in the meta-data RDF graph to a human-friendly integer text identifier. """

        try:
            return validate_etextno(int(os.path.basename(uri_ref.toPython())))
        except InvalidEtextIdException:
            return None