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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 _openapi_redoc(self):
 """ Expose OpenAPI spec with ReDoc The ReDoc script URL can be specified as ``API_REDOC_SOURCE_URL`` """

        return render_template('openapi/redoc.html',
                               title=self.app.config.API_TITLE or self.app.name,
                               redoc_url=self.app.config.API_REDOC_SOURCE_URL)