How to forbid two conflicting options

Question

Is there a way to specify to Python's ArgumentParser that two optional flags are conflicting?

arg_parser.add_argument('-c', '--clean', action='store_true')
arg_parser.add_argument('-d', '--dirty', action='store_true')

I want the user to be able to specify either none of those, or only one.

Is it achievable without further conditions?

Answer 1

How about adding a mutually exclusive group:

group = arg_parser.add_mutually_exclusive_group()
group.add_argument('-c', '--clean', action='store_true')
group.add_argument('-d', '--dirty', action='store_true')

with this I get the following behaviour:

>>> arg_parser.parse_args(['--clean']) 
Namespace(clean=True, dirty=False)
>>> arg_parser.parse_args(['--dirty']) 
Namespace(clean=False, dirty=True)
>>> arg_parser.parse_args(['--dirty','--clean']) 
usage: PROG [-h] [-c | -d] PROG: error: argument -c/--clean: not allowed with argument -d/--dirty