docs: def make_wsgi_app(registry=REGISTRY):
      """Create a WSGI app which serves the metrics from a registry."""
  
      def prometheus_app(environ, start_response):
          params = parse_qs(environ.get('QUERY_STRING', ''))
          r = registry
          encoder, content_type = choose_encoder(environ.get('HTTP_ACCEPT'))
          if 'name[]' in params:
              r = r.restricted_registry(params['name[]'])
          output = encoder(r)
  
          status = str('200 OK')
          headers = [(str('Content-type'), content_type)]
          start_response(status, headers)
          return [output]
  
      return prometheus_app