[Python] argparse action or type for comma-separated list

I want to create a command line flag that can be used as

./prog.py --myarg=abcd,e,fg


and inside the parser have this be turned into ['abcd', 'e', 'fg'] (a tuple would be fine too).

I have done this successfully using action and type, but I feel like one is likely an abuse of the system or missing corner cases, while the other is right. However, I don't know which is which.

With action:

import argparse

class SplitArgs(argparse.Action):
def __call__(self, parser, namespace, values, option_string=None):
setattr(namespace, self.dest, values.split(','))


parser = argparse.ArgumentParser()
parser.add_argument('--myarg', action=SplitArgs)
args = parser.parse_args()
print(args.myarg)


Instead with type:

import argparse

def list_str(values):
return values.split(',')

parser = argparse.ArgumentParser()
parser.add_argument('--myarg', type=list_str)
args = parser.parse_args()
print(args.myarg)

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