class Brief { List? img; Brief({ this.img, }); factory Brief.fromJson(Map json) => Brief( img: (json['img'] as List?)?.map((e) => Img.fromJson(e)).toList(), ); } class Img { num aspectRatio; String? url; Img({ required this.aspectRatio, this.url, }); factory Img.fromJson(Map json) => Img( aspectRatio: json['aspect_ratio'] ?? 1, url: json['url'] as String?, ); }