OpenStack os_server os_volume multiple instance launch

Hello,

I am trying to launch/create multiple instances and attach multiple
volumes with a loop but not having much luck. I can get it to work if
I define each instance/volume but who wants to do that? Ideally I
would set a var that says something like make 100 instances. Below is
an example of what I currently have. How to I transfor these into
loops?