__init__.py 文件源码

def apply(self, from_version, to_version, data):
        strict_from = distutils.version.StrictVersion(from_version)
        strict_to = distutils.version.StrictVersion(to_version)
        assert strict_from <= strict_to, \
            "from_version must not be greater than to_version"
        data = copy.deepcopy(data)
        for version, transformers in self.transformers:
            if version <= strict_from:
                continue
            if version > strict_to:
                break
            for transformer in transformers:
                LOG.debug("Applying %s transformer %s",
                          self.name, transformer)
                data = transformer(data)
        return data