Custom Argument Parser class to use argparse in REST api app

ArgumentParser.py

from argparse import ArgumentParser
import sys as _sys


# Tested on Python 3.8. For version >=3.9, There is new exit_on_error flag in init function.
# Although it doesn't entirely help our use case, we should be passing our flag `exit_on_error`
# to the parent class init function.

class CustomArgumentParser(ArgumentParser):
    def __init__(self, prog=None, exit_on_error=False):
        self.exit_on_error = exit_on_error
        super().__init__(prog=prog)

    def exit(self, status=0, message=None):
        if message:
            self._print_message(message, _sys.stdout)

        if self.exit_on_error:
            _sys.exit(status)

    def error(self, message):
        """error(message: string)

        Prints a usage message incorporating the message to stdout and
        exits if respective class is provided.
        """
        self.print_usage(_sys.stdout)
        args = {"prog": self.prog, "message": message}
        self.exit(2, "%(prog)s: error: %(message)s\n" % args)