Installing pip

We are going to use the pip (or pip3) tool to install the libraries, so—if it isn't already installed—we need to install pip first. As mentioned here (https://pip.pypa.io/en/stable/installing/#do-i-need-to-install-pip), pip is already installed if we are using Python 3 >=3.4 downloaded from python.org, or if we are working in a Virtual Environment (https://packaging.python.org/tutorials/installing-packages/#creating-and-using-virtual-environments) created by virtualenv (https://packaging.python.org/key_projects/#virtualenv) or pyvenv (https://packaging.python.org/key_projects/#venv). We just need to make sure to upgrade pip (https://pip.pypa.io/en/stable/installing/#upgrading-pip). How to install pip for different OSes or platforms can be found here: https://stackoverflow.com/questions/6587507/how-to-install-pip-with-python-3.