def get_arg_parser (self, **kwargs):
        """Return an instance of `argparse.ArgumentParser` used to process
        this tool's command-line arguments.

        """
        import argparse
        ap = argparse.ArgumentParser (
            prog = kwargs['argv0'],
            description = self.summary,
        )
        return ap
Return an instance of `argparse.ArgumentParser` used to process
        this tool's command-line arguments.