Virtual environment will create a default virtual environment
Following the steps in readme if a user creates Virtual Environment (VE), the user will get a VE on the basis of systems default Python. The problem is if the default Python is 2.7 then the user will get Python 2.7 VE however, the tox is looking for Python 3.6 as a result the tests may fail.
Better would be to create VE with the specified version so the command to create VE could be changed from
virtualenv mynewprojct_virtualenv to
virtualenv -p python3 mynewprojct_virtualenv.
This will create VE of Python version 3 and give an error if Python 3 is not installed. In the later case the user can install Python 3.