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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 from_backend(self, dagobah_id):
 """ Reconstruct this Dagobah instance from the backend. """

        logger.debug('Reconstructing Dagobah instance from backend with ID {0}'.format(dagobah_id))
        rec = self.backend.get_dagobah_json(dagobah_id)
        if not rec:
            raise DagobahError('dagobah with id %s does not exist '
                               'in backend' % dagobah_id)
        self._construct_from_json(rec)