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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 fetch(self):
 """ Retrieves the content of the current document from the remote database and populates the locally cached Document object with that content. A call to fetch will overwrite any dictionary content currently in the locally cached Document object. """

        if self.document_url is None:
            raise CloudantDocumentException(101)
        resp = self.r_session.get(self.document_url)
        resp.raise_for_status()
        self.clear()
        self.update(response_to_json_dict(resp, cls=self.decoder))