Passing an argument to an operator

To wrap up this thread and provide a tl;dr for those who come looking later: you can’t exactly call an operator with an argument in the same way you can with a function or method.

But you can pass options to operators with properties. This can be helpful if you want to call an operator with a limited preset set of options.

Setting a property from a panel

See @batFINGER’s post here, with code:

Setting a property with a keybinding

See @iceythe’s post in this thread, also with code:

Dynamically creating an operator for each ‘argument’

I include this as another potential option: if you are going to have a small number of presets, you can dynamically create operators for each preset. I give an example in this thread:

(post #8, see also API reference on ‘Dynamic Class Definition’)