What is wrong with qt5 libs? - python-3.x

Question

I tried to code simple exercise on qt5:
main.py:
import sys
from PySide2.QtWidgets import QApplication, QLabel
app = QApplication(sys.argv)
label = QLabel("Hello World!")
label.show()
app.exec_()
When I tried to start I got errors which are linked with Qt5 libs:
(base) [redf1sh#redPC ~]$ export QT_DEBUG_PLUGINS=1
(base) [redf1sh#redPC ~]$ python3 main.py
...
Got keys from plugin meta data ("xcb")
QFactoryLoader::QFactoryLoader() checking directory path "/home/redf1sh/anaconda3/bin/platforms" ...
Cannot load library /home/redf1sh/anaconda3/plugins/platforms/libqxcb.so: (/home/redf1sh/anaconda3/plugins/platforms/../../lib/libQt5XcbQpa.so.5: undefined symbol: _ZN11QFontEngine14bitmapForGlyphEj6QFixedRK10QTransform, version Qt_5_PRIVATE_API)
QLibraryPrivate::loadPlugin failed on "/home/redf1sh/anaconda3/plugins/platforms/libqxcb.so" : "Cannot load library /home/redf1sh/anaconda3/plugins/platforms/libqxcb.so: (/home/redf1sh/anaconda3/plugins/platforms/../../lib/libQt5XcbQpa.so.5: undefined symbol: _ZN11QFontEngine14bitmapForGlyphEj6QFixedRK10QTransform, version Qt_5_PRIVATE_API)"
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
Available platform plugins are: eglfs, minimal, minimalegl, offscreen, vnc, xcb.
I've installed pyqt5 packages, pyside2 with pip.
Can you help me with this?

Answer 1

I solved it by myself.
Firstly, I found all packages in the system that are connected to qt and removed them:
$ pip list | grep qt
$ pip uninstall *smth*
$ conda list | grep qt
$ conda remove *smth*
$ pacman -Qe | grep qt
# pacman -R *smth*
and secondly is clear install only from pacman (not plugins in pip or conda)
# pacman -S qt5 pyside2 python-pyqt5
and now all is working well