Can't launch setup.py in Docker image - module named 'flask'

but got the error:

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Traceback (most recent call last):
  File "/pgadmin4/setup.py", line 33, in <module>
    from pgadmin.model import db, User, Version, ServerGroup, Server, \
  File "/pgadmin4/pgadmin/__init__.py", line 23, in <module>
    from flask import Flask, abort, request, current_app, session, url_for
ModuleNotFoundError: No module named 'flask'

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So, if it can't be launched manually, it must fail on automatic servers import process too?

Is this a missing package in Docker image, or some misconfiguration?

And is there any other ways to debug the applying servers.json process?

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