def __init__(self, name, mode=None,
                 description='', default=None, validator=None):
        if mode is None:
            mode = self.OPTIONAL
        elif not isinstance(mode, int) or mode > 7 or mode < 1:
            raise Exception('Argument mode "%s" is not valid.' % mode)

        self.__name = name
        self.__mode = mode
        self.__description = description or ''
        self.__validator = VALIDATORS.get(validator)

        self.set_default(default)
Creates a regular expression used to match against S3 keys
dataset/ETHPy150Open sdispater/cleo/cleo/inputs/input_argument.py/InputArgument.__init__--crossover with--dataset/ETHPy150Open aws/aws-cli/awscli/customizations/cloudtrail/validation.py/DigestProvider._create_digest_key_regex