A thousand thankyous to you kellemes.
Event Tester showed me that my F7 button does nothing when [U]I[U] press it, but what I could see from the Terminal window was that it was repeatedly activating itself (??) and, like you, my keycode is 73.
Interestingly, Fn+F7, which is a HotKey to toggle my touchpad on/off DOES work and from that I am also able to see that the keycode is 73.
I entered your piece of code and my F7 key is now silent
You may or may not be interested to hear that Fn+F7 still toggles my touchpad on/off..
Does this give any clue as to what the problem is?
Next step is to make it permanent.. I will post news of that next and hopefully this can become a useful thread for others.