docstr: save a instance of User() to user data path
      Parameter
          user_id : string
docstr_tok: ["save","a","instance","of","User","(",")","to","user","data","path","Parameter","user_id",":","string"]
code: def save_user_data(self, user_id):
      """
      save a instance of User() to user data path
          Parameter
              user_id : string
      """
      if not user_id in self.users:
          raise ValueError("Cannot find user {}".format(user_id))
      self.users[user_id].account.save_account(self.data_path / user_id)
      save_instance(
          self.users[user_id].strategy,
          self.data_path
          / user_id
          / "strategy_{}.pickle".format(user_id),
      )
      save_instance(
          self.users[user_id].model,
          self.data_path / user_id / "model_{}.pickle".format(user_id),
      )
  
file_path: qlib/qlib/contrib/online/manager.py
imports: import yaml
  import pathlib
  import pandas
  import shutil
  from ...backtest.account import Account
  from .user import User
  from .utils import load_instance, save_instance
  from ...utils import init_instance_by_config
label_desc: Use image node_id 4 for calling the UserManager obj's underlying member method code with example usage: obj.save_user_data(user_id) without return types