I was using the terminal (Mac OS) for a python 3 flask module application. I needed to use sudo:
python3 -m venv flask
sudo easy-install virtualenv
Sudo asked me for my sudo password, and I put it in. Here's what it threw at me:
sorry, try again
The website your are linking at says the following between these code lines:
Note that in some operating systems you may need to use python3 instead of python. The above command creates a private version of your Python interpreter inside a folder named flask.
If you are using any other version of Python older than 3.4, then you need to download and install virtualenv.py before you can create a virtual environment. If you are on Mac OS X, then you can install it with the following command.
It could be that you are using the wrong Python version or that you haven't virtualenv.py installed.