return self.view_functions[rule.endpoint](**req.view_args)
  File "/Users/liujun/PycharmProjects/lean-flask/web/controllers/User.py", line 78, in edit
    db.session.add(user_info)
  File "/Users/liujun/.pyenv/versions/3.6.2/envs/env362/lib/python3.6/site-packages/sqlalchemy/orm/scoping.py", line 162, in do
    return getattr(self.registry(), name)(*args, **kwargs)
  File "/Users/liujun/.pyenv/versions/3.6.2/envs/env362/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 1947, in add
    self._save_or_update_state(state)
  File "/Users/liujun/.pyenv/versions/3.6.2/envs/env362/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 1960, in _save_or_update_state
    self._save_or_update_impl(state)
  File "/Users/liujun/.pyenv/versions/3.6.2/envs/env362/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 2303, in _save_or_update_impl
    self._update_impl(state)
  File "/Users/liujun/.pyenv/versions/3.6.2/envs/env362/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 2286, in _update_impl
    to_attach = self._before_attach(state, obj)
  File "/Users/liujun/.pyenv/versions/3.6.2/envs/env362/lib/python3.6/site-packages/sqlalchemy/orm/session.py", line 2374, in _before_attach
    % (state_str(state), state.session_id, self.hash_key)
sqlalchemy.exc.InvalidRequestError: Object '<User at 0x10e4a3828>' is already attached to session '1' (this is '2')

我在修改昵称或邮箱后，提交报错，百度说是db.session不一致的问题，但还是没有明白，麻烦老师帮忙看下