toJson method
Implementation
core.Map<core.String, core.dynamic> toJson() => {
if (id != null) 'id': id!,
if (items != null) 'items': items!,
if (nextPageToken != null) 'nextPageToken': nextPageToken!,
if (selfLink != null) 'selfLink': selfLink!,
if (warning != null) 'warning': warning!,
};