optparse.option action=“store” with no parameter

Question

I want to make a bool arg into a store arg with presence on cli with no provided value as a legal setting:

prog.py [--nuke [name1[,name2]*]]  # clean usual + optional csv string 

eg

prog.py                       # no action
prog.py --nuke                # usual clean
prog.py --nuke special,value  # extra named clean csv value special

Realizing the simplest answer to this question is to have 2 options. But without stretching imagination too far, Id like to be very conservative with options.

I am trying to have empty parameter as a legal option. I presence of the parameter with no args is legal. Can I do this with a single parameter?

def pytest_addoption(parser):
  parser.addoption('--nuke', action="store", default=False,
                   help="pass in named object to delete, or empty to "  
                        "delete usual-suspects. eg. "
                        "  prog --nuke   # remove all but host"
                        "  prog --nuke templates  # all but host plus named vm")

Answer 1

Most familiar approach: make it 2 options instead of 1 --nuke(action=store_true); --doomed(action=append);

presence of 'nuke' implies do the default action. presence of 'doomed' implies modify nuke targets.