code: def post(self):
          
          self.set_header("Content-Type", "application/json")
          key = uuid.uuid4().hex
          metadata = json.loads(self.request.body.decode())
          metadata["uuid"] = key
          self.database[key] = metadata
          result = json.dumps({"uuid": key})
          self.write(result)
docs: Register a new model (models)