from flask import Flask
app = Flask(__name__)

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

if __name__ == '__main__':
    import sys, os
    if len(sys.argv) > 1:
        # arg, if any, is the desired port number
        port = int(sys.argv[1])
        assert(port>1024)
    else:
        port = os.getuid()
    app.debug = True
    app.run('0.0.0.0',port)