Python: different argparse for multiple classes launched from the same file

I'm developing an environment for experiments. Each experiment is a separate class has a different arguments required. The concept is to have a set of arguments that are related to the whole experimenting environment and a set of arguments imported from an experiment class. The question is: how to update possible arguments accordingly to chosen experiment type.

How i would love to make it basically looks like:

Note: EXPERIMENTS is a dict with experiment classes mapped by their names

main.py

def main(args):
    experiment()

if __name__ == "__main__":
    parser = argparse.ArgumentParser()

    parser.add_argument("experiment_name",
                        metavar='experiment_name',
                        type=str,
                        choices=EXPERIMENTS.keys(), #exported list of available experiments
                        help="Choose an experiment to run. Available: "+str(list(EXPERIMENTS.keys())),
                        )
    args = parser.parse_args()
    EXPERIMENTS[args.experiment_name].add_args(parser)

    experiment = EXPERIMENTS[args.experiment_name]()

    sys.exit(main(args) or 0) 

experimentA.py

class ExperimentA(Experiment):
    
    @classmethod
    def add_args(cls, parser):
        parser.add_argument('--expA-arg')
        cls.args = parser.parse_args()
    
    def __init__(self):
        super().__init__()
        self.args = self.__class__.args
        self.param = self.args.expA_arg

    def __call__(self):
        run_the_experiment_A()

experimentB.py

class ExperimentB(Experiment):
    
    @classmethod
    def add_args(cls, parser):
        parser.add_argument('--expB-arg')
        cls.args = parser.parse_args()
    
    def __init__(self):
        super().__init__()
        self.args = self.__class__.args
        self.param = self.args.expB_arg

    def __call__(self):
        run_the_experiment_B()

And how to achieve it to see those results after calling from shell:

case 1

IN:

python3 main.py -h

OUT:

positional arguments:
  experiment_name  Choose an experiment to run. Available: ['ExperimentA', 'ExperimentB']

optional arguments:
  -h, --help       show this help message and exit

case 2

IN:

python3 main.py ExperimentA -h

OUT:

positional arguments:
  experiment_name  Choose an experiment to run. Available: ['ExperimentA', 'ExperimentB']

optional arguments:
  -h, --help       show this help message and exit
  --expA-arg       

case 3

IN:

python3 main.py ExperimentB -h

OUT:

positional arguments:
  experiment_name  Choose an experiment to run. Available: ['ExperimentA', 'ExperimentB']

optional arguments:
  -h, --help       show this help message and exit
  --expB-arg