Example CLI help output for possible re-implementation of boolean flags for begins.

flask_quickstart.py

from flask import Flask
import begin

app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello World!'

@begin.start(env_prefix='WEB_')
@begin.convert(port=int, debug=begin.utils.tobool)
def main(host='127.0.0.1', port=8080, debug=False):
    app.run(host=host, port=port, debug=debug)

gistfile1.txt

$ WEB_DEBUG=false python flask_quickstart.py --help
usage: flask_quickstart.py [--help] [--host WEB_HOST] [--port WEB_PORT]
                           [--debug] [--no-debug]

optional arguments:
  --help                show this help message and exit
  --host WEB_HOST, -h WEB_HOST
                        (default: 127.0.0.1)
  --port WEB_PORT, -p WEB_PORT
                        (default: 8080)
  --debug               (default: False)
  --no-debug

gistfile2.txt

$ WEB_DEBUG=true python flask_quickstart.py --help
usage: flask_quickstart.py [--help] [--host WEB_HOST] [--port WEB_PORT]
                           [--debug] [--no-debug]

optional arguments:
  --help                show this help message and exit
  --host WEB_HOST, -h WEB_HOST
                        (default: 127.0.0.1)
  --port WEB_PORT, -p WEB_PORT
                        (default: 8080)
  --debug
  --no-debug            (default: True)