[Python] Make argparse treat dashes and underscore identically

argparse replaces dashes in optional arguments by underscores to determine their destination:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--use-unicorns', action='store_true')
args = parser.parse_args(['--use-unicorns'])
print(args) # returns: Namespace(use_unicorns=True)


However the user has to remember whether the option is --use-unicorns or --use_unicorns; using the wrong variant raises an error.

This can cause some frustration as the variable args.use_unicorns in the code does not make it clear which variant was defined.

How can I make argparse accept both --use-unicorns and --use_unicorns as valid ways to define this optional argument?

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