python和vnpy都安装完成，安装过程中没有任何错误提示。
在启动vnpy却报了No module named 'sqlalchemy.ext.declarative.api'。
查看python库中安装了SQLAlchemy 1.4.2，但库里的路径里的确没有'sqlalchemy.ext.declarative.api'这个模块。
是否对SQLAlchemy有特别的版本要求，导致模块没有？

PS C:\downloads\vnpy\examples\vn_trader> python -V
Python 3.7.9
PS C:\downloads\vnpy\examples\vn_trader> python run.py
Traceback (most recent call last):
File "run.py", line 5, in <module>
from vnpy.trader.ui import MainWindow, create_qapp
File "C:\Users\liuxi\AppData\Local\Programs\Python\Python37\lib\site-packages\vnpy\trader\ui__init.py", line 11, in <module>
from .mainwindow import MainWindow
File "C:\Users\liuxi\AppData\Local\Programs\Python\Python37\lib\site-packages\vnpy\trader\ui\mainwindow.py", line 14, in <module>
from .widget import (
File "C:\Users\liuxi\AppData\Local\Programs\Python\Python37\lib\site-packages\vnpy\trader\ui\widget.py", line 13, in <module>
import rqdatac
File "C:\Users\liuxi\AppData\Local\Programs\Python\Python37\lib\site-packages\rqdatac\init.py", line 21, in <module> go()
File "C:\Users\liuxi\AppData\Local\Programs\Python\Python37\lib\site-packages\rqdatac__init.py", line 18, in go
importlib.import_module(module_name)
File "C:\Users\liuxi\AppData\Local\Programs\Python\Python37\lib\importlib__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "C:\Users\liuxi\AppData\Local\Programs\Python\Python37\lib\site-packages\rqdatac\services\financial.py", line 17, in <module>
from sqlalchemy.ext.declarative.api import DeclarativeMeta
ModuleNotFoundError: No module named 'sqlalchemy.ext.declarative.api'

请在cmd中运行：

pip install sqlalchemy==1.3.13

降级下版本

用Python的交易员 wrote:

请在cmd中运行：

pip install sqlalchemy==1.3.13

降级下版本

降到1.3.13已经可以启动，多谢！