code: func (g *Cloud) ListURLMaps() ([]*compute.UrlMap, error) {
  	ctx, cancel := cloud.ContextWithCallTimeout()
  	defer cancel()
  
  	mc := newURLMapMetricContext("list")
  	v, err := g.c.UrlMaps().List(ctx, filter.None)
  	return v, mc.Observe(err)
  }
docs: // ListURLMaps lists all UrlMaps in the project.