我的笔记本电脑上已经安装了flask，但是仍然没有弹出名为flask的模块以及dpkg错误。我尝试了来自各种站点的几种解决方案，例如：
1. sudo dpkg --configure -a
2. sudo apt-get install -f
3. sudo apt-get purge apache2 apache2-data apache2-utils
但是每次我遇到同样的问题。请帮助我。
Setting up pgadmin4-apache2 (4.23-1.pgdg18.04+1) ...
apache2_invoke pgadmin4: already enabled
Traceback (most recent call last):
File "setup.py", line 18, in <module>
from pgadmin.model import db, User, Version, ServerGroup, Server, \
File "/usr/share/pgadmin4/web/pgadmin/__init__.py", line 19, in <module>
from flask import Flask, abort, request, current_app, session, url_for
ModuleNotFoundError: No module named 'flask'
dpkg: error processing package pgadmin4-apache2 (--configure):
installed pgadmin4-apache2 package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
pgadmin4-apache2
E: Sub-process /usr/bin/dpkg returned an error code (1)