Lirc in virtual environment

I just got started with the rpi and HA using the all in one installer. I’m following the instructions on the LIRC page. https://home-assistant.io/components/lirc/

I’m stuck at this point.
“As the user that runs hass”

How do I change user to hass? I went searching around and found this command. sudo su -s /bin/bash hass

I think that’s right, is it?

Then when I do the following commands
(hass) $ git clone https://github.com/tompreston/python-lirc.git
(hass) $ cd python-lirc
(hass) $ make py3

On “make py3” I get the following error
“hass@raspberrypi:~/python-lirc$ make py3
cython -3 -a lirc/lirc.pyx
make: cython: Command not found
Makefile:2: recipe for target ‘py3’ failed
make: *** [py3] Error 127
hass@raspberrypi:~/python-lirc$”

any help would be greatly appreciated thanks