def upgrade(self, from_version=None, to_version=__version__):
        if from_version is None:
            try:
                from_version = self._read_md()['properties']['db-version']
            except (KeyError, __HOLE__):
                from_version = "0.0"

        self.upgrade_steps.run(self, from_version, to_version)
        md = self._read_md()
        md['properties']['db-version'] = to_version
        self._update_md(md)
dataset/ETHPy150Open ottogroup/palladium/palladium/persistence.py/File.upgrade