code: def flaskrun(app, default_host="127.0.0.1", default_port="8000"):
      
  
      # Set up the command-line options
      parser = optparse.OptionParser()
      parser.add_option(
          "-H",
          "--host",
          help="Hostname of the Flask app " + "[default %s]" % default_host,
          default=default_host,
      )
      parser.add_option(
          "-P",
          "--port",
          help="Port for the Flask app " + "[default %s]" % default_port,
          default=default_port,
      )
  
      # Two options useful for debugging purposes, but
      # a bit dangerous so not exposed in the help message.
      parser.add_option(
          "-d", "--debug", action="store_true", dest="debug", help=optparse.SUPPRESS_HELP
      )
      parser.add_option(
          "-p",
          "--profile",
          action="store_true",
          dest="profile",
          help=optparse.SUPPRESS_HELP,
      )
  
      options, _ = parser.parse_args()
  
      # If the user selects the profiling option, then we need
      # to do a little extra setup
      if options.profile:
          from werkzeug.contrib.profiler import ProfilerMiddleware
  
          app.config["PROFILE"] = True
          app.wsgi_app = ProfilerMiddleware(app.wsgi_app, restrictions=[30])
          options.debug = True
  
      app.run(debug=options.debug, host=options.host, port=int(options.port))
docs: Takes a flask.Flask instance and runs it. Parses
      command-line flags to configure the app.