to execute the commands read from the file. click.command() [https://click.palletsprojects.com/en/8.0.x/api/#click.command] defines a command line command called init-db that calls the init_db function cleaning up after returning the response. app.cli.add_command() [https://click.palletsprojects.com/en/8.0.x/api/#click.Group.add_command] adds a new command that can be called with the flask command. Import [https://click.palletsprojects.com/en/8.0.x/api/#click.testing.CliRunner] runs commands in isolation and captures the output in a Result [https://click.palletsprojects.com/en/8.0.x/api/#click.testing.Result] object