def save(self, doc):
        if doc.id:
            return self.update(doc)
        else:
            return self.insert(doc)
def list_snapshots(self, params=None):
        """List all the snapshot."""
        url = 'snapshots'
        if params:
                url += '?%s' % urllib.urlencode(params)

        resp, body = self.get(url)
        body = json.loads(body)
        return resp, body['snapshots']