code: def build_application(conf):
      
      if isinstance(conf.adapter_options, list):
          conf['adapter_options'] = {key: val for _dict in conf.adapter_options
                                     for key, val in _dict.items()}
      elif conf.adapter_options is None:
          conf['adapter_options'] = {}
      else:
          conf['adapter_options'] = copy.copy(conf.adapter_options)
  
      # get wsgi app the same way bottle does if it receives a string.
      conf['app'] = conf.app or bottle.default_app()
      if isinstance(conf.app, six.string_types):
          conf['app'] = bottle.load_app(conf.app)
  
      def _find_bottle_app(_app):
          """Lookup the underlying Bottle() instance."""
          while hasattr(_app, 'app'):
              if isinstance(_app, bottle.Bottle):
                  break
              _app = _app.app
          assert isinstance(_app, bottle.Bottle), 'Could not find Bottle app.'
          return _app
  
      bottle_app = _find_bottle_app(conf.app)
      bottle_app.route(
          path='/_simpl', method='GET', callback=_version_callback)
  
      def _show_routes():
          """Conditionally print the app's routes."""
          if conf.app and not conf.quiet:
              if conf.reloader and os.getenv('BOTTLE_CHILD'):
                  LOG.info("Running bottle server with reloader.")
              elif not conf.reloader:
                  pass
              else:
                  return
              routes = fmt_routes(bottle_app)
              if routes:
                      print('\n{}'.format(routes), end='\n\n')
      _show_routes()
      return conf.app
docs: Do some setup and return the wsgi app.