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#its work 100%
#in python 3.8 you can use your python version
sudo ln -s /usr/bin/python3.8 /usr/bin/python
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1. Check current version:
$ python --version
2. get root permissions:
$ sudo su
3. set python3 as default:
$ update-alternatives --install /usr/bin/python python /usr/bin/python3 1
4. Done. (Check by $ python --version)