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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 _load_sensors(self, path=None):
 """Load sensors from file."""

        if path is None:
            path = self.persistence_file
        exists = os.path.isfile(path)
        if exists and os.access(path, os.R_OK):
            if path == self.persistence_bak:
                os.rename(path, self.persistence_file)
                path = self.persistence_file
            _LOGGER.debug('Loading sensors from persistence file %s', path)
            self._perform_file_action(path, 'load')
            return True
        _LOGGER.warning('File does not exist or is not readable: %s', path)
        return False