Hi, thanks for the effort. It's strange, because typing "rate" + space should show the workflow name and icon, doesn't matter if the workflow works properly or not.
Was the workflow installed properly? (does it show up in the "Workflows" tab of the Alfred preferences?)
What version of Alfred and python do you have?
You may try enabling debug for this workflow (select the workflow, click small bug icon in the right corner) and see if there are any debug messages.