I started the Django's shell using:
python3 manage.py shell
but weirdly the python interpreter is kicking off instead (I see >>> instead of [n]:, and the initializing text contains no Django information, besides the main imports for the shell aren't executed)
considering that: I'm in ubuntu 20.04, It was running with no problem with python instead of python3, now python isn't recognized but it's linked to python3 so no difference "isn't it??!".