我正在使用flask-admin 和flask-sqlalchemy 开发一个小型flask API。api 运行良好，但每当我安装新包时，我都会遇到错误。
Error: While importing 'app', an ImportError was raised:
Traceback (most recent call last):
File "/Users/brandoncreed/.local/share/virtualenvs/management-System-Wyc_ba1N/lib/python3.8/site-packages/flask/cli.py", line 218, in locate_app
__import__(module_name)
File "/Users/brandoncreed/Desktop/Brandon Coding Projects/management-System/src/app.py", line 12, in <module>
from api.admin import setup_admin
File "/Users/brandoncreed/Desktop/Brandon Coding Projects/management-System/src/api/admin.py", line 5, in <module>
from flask_admin.contrib.sqla import ModelView
File "/Users/brandoncreed/.local/share/virtualenvs/management-System-Wyc_ba1N/lib/python3.8/site-packages/flask_admin/contrib/sqla/__init__.py", line 2, in <module>
from .view import ModelView
File "/Users/brandoncreed/.local/share/virtualenvs/management-System-Wyc_ba1N/lib/python3.8/site-packages/flask_admin/contrib/sqla/view.py", line 18, in <module>
from flask_admin.contrib.sqla.tools import is_relationship
File "/Users/brandoncreed/.local/share/virtualenvs/management-System-Wyc_ba1N/lib/python3.8/site-packages/flask_admin/contrib/sqla/tools.py", line 11, in <module>
from sqlalchemy.ext.associationproxy import ASSOCIATION_PROXY
ImportError: …