#!/usr/bin/env python
# encoding: utf-8
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"""A trivial program that adds two numbers with Guacamole."""

from __future__ import absolute_import, print_function, unicode_literals

from guacamole import Command


class Addder(Command):

    """Add two numbers together."""

    def register_arguments(self, parser):
        """
        Guacamole method used by the argparse ingredient.

        :param parser:
            Argument parser (from :mod:`argparse`) specific to this command.
        """
        parser.add_argument('x', type=int, help='the first value')
        parser.add_argument('y', type=int, help='the second value')

    def invoked(self, ctx):
        """
        Guacamole method used by the command ingredient.

        :param ctx:
            The guacamole context object. Context provides access to all
            features of guacamole. The argparse ingredient adds the ``args``
            attribute to it. That attribute contains the result of parsing
            command line arguments.
        :returns:
            The return code of the command. Guacamole translates ``None`` to a
            successful exit status (return code zero).
        """
        print("{} + {} = {}".format(
            ctx.args.x,
            ctx.args.y,
            ctx.args.x + ctx.args.y))


if __name__ == '__main__':
    Addder().main()