I already tried several options like these, but all I am getting are errors, like this one:

python setup.py 

    build_ui 

    build_py -c -d . 

    build_mo

running build_ui

running build_py

running build_mo

HGRCPATH= python thg version

Traceback (most recent call last):

  File "thg", line 99, in <module>

    tortoisehg.hgqt.run.run()

  File "/usr/lib/python3.8/importlib/util.py", line 245, in __getattribute__

    self.__spec__.loader.exec_module(self)

  File "<frozen importlib._bootstrap_external>", line 783, in exec_module

  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed

  File "/home/user/thg/tortoisehg/hgqt/run.py", line 499, in <module>

    _('repository root directory or symbolic path name')),

  File "/home/user/thg/tortoisehg/util/i18n.py", line 109, in agettext

    return hglib.fromunicode(u)

  File "/usr/lib/python3.8/importlib/util.py", line 245, in __getattribute__

    self.__spec__.loader.exec_module(self)

  File "<frozen importlib._bootstrap_external>", line 783, in exec_module

  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed

  File "/home/user/thg/tortoisehg/util/hglib.py", line 351, in <module>

    readmergestate = mergemod.mergestate.read

  File "/usr/lib/python3.8/importlib/util.py", line 256, in __getattribute__

    return getattr(self, attr)

AttributeError: module 'mercurial.merge' has no attribute 'mergestate'

make: *** [Makefile:25: local] Error 1

Or this one after installing pyqt5:

    from PyQt5.QtCore import *

ImportError: No module named PyQt5.QtCore

make: *** [Makefile:24: local] Error 1

In case it is needed, my python version is 3.8.2