def load(self, filename, create_if_missing=True):
        filename = Path(filename)
        if not filename.exists() and create_if_missing:
            self.load_pip_requirements()
            with filename.open("w") as f:
                f.write(yaml.dump(self.serialized, default_flow_style=False,
                                  encoding=None))
            self.filename = filename
            return self.save(filename)
        with filename.open() as f:
            for group, requirements in yaml.load(f.read()).items():
                for requirement in requirements:
                    self[group].add(Requirement.coerce(requirement))
        self.filename = filename
def create_snapshot_metadata(self, snapshot_id, metadata):
        """Create metadata for the snapshot."""
        put_body = json.dumps({'metadata': metadata})
        url = "snapshots/%s/metadata" % str(snapshot_id)
        resp, body = self.post(url, put_body)
        body = json.loads(body)
        return resp, body['metadata']