code: def serve_static(self, environ, coll='', filepath=''):
          
          proxy_enabled = self.is_proxy_enabled(environ)
          if proxy_enabled and environ.get('REQUEST_METHOD') == 'OPTIONS':
              return WbResponse.options_response(environ)
          if coll:
              path = os.path.join(self.warcserver.root_dir, coll, self.static_dir)
          else:
              path = self.static_dir
  
          environ['pywb.static_dir'] = path
          try:
              response = self.static_handler(environ, filepath)
              if proxy_enabled:
                  response.add_access_control_headers(env=environ)
              return response
          except:
              self.raise_not_found(environ, 'Static File Not Found: {0}'.format(filepath))
docs: Serve a static file associated with a specific collection or one of pywb's own static assets
  
          :param dict environ: The WSGI environment dictionary for the request
          :param str coll: The collection the static file is associated with
          :param str filepath: The file path (relative to the collection) for the static assest
          :return: The WbResponse for the static asset
          :rtype: WbResponse