docs: def get_app_url(self):
          """
          Returns the application URL as defined in the INI section
          `server:main`. Defaults to `http://0.0.0.0/6543`.
          """
          section = 'server:main'
          if self.has_setting(section, 'host'):
              host = self.get_setting(section, 'host')
          else:
              host = '0.0.0.0'
          if self.has_setting(section, 'port'):
              port = int(self.get_setting(section, 'port'))
          else:
              port = 6543
          return 'http://%s:%d' % (host, port)