code: func parseVirtualNetwork(name string, defaultRG string) (string, string) {
  	l := strings.SplitN(name, ":", 2)
  	if len(l) == 2 {
  		return l[0], l[1]
  	}
  	return defaultRG, name
  }
docs: // parseVirtualNetwork parses Virtual Network input format "[resourcegroup:]name"
  // into Resource Group (uses provided one if omitted) and Virtual Network Name