As @

already mentioned it, you can go for the command: python3
prerequisites: you already installed it.
If you want to use the command 'python' as an alias of 'python3' - just
make use of your home bashrc and add an alias.
like:
~/.bashrc or ~/.bash_aliases
Code:
alias python=python3
Take care, if you run custom shell scripts, which probably a part of an automated process, you should
avoid adding aliases - since they would run with python3 instead of python2.7 and might cause conflicts in your process routine.