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(self, volume_id, **kwargs):
        """
        Creates a new snapshot.
        volume_id(Required): id of the volume.
        force: Create a snapshot even if the volume attached (Default=False)
        display_name: Optional snapshot Name.
        display_description: User friendly snapshot description.
        """
        post_body = {'volume_id': volume_id}
        post_body.update(kwargs)
        post_body = json.dumps({'snapshot': post_body})
        resp, body = self.post('snapshots', post_body)
        body = json.loads(body)
        return resp, body['snapshot']