想问下这句 oc 代码用 swfit3 应该怎么调用

最近在用 oc 到 swift 的迁移，对 swift 实在生疏，oc 中的 TZImagePickController 中有这么一个属性

@property (nonatomic, copy) void (^didFinishPickingPhotosHandle)(NSArray<UIImage *> *photos,NSArray *assets,BOOL isSelectOriginalPhoto);

先前的调用方式是这样的

`[imagePickerVc setDidFinishPickingPhotosHandle:^(NSArray<UIImage *> *photos, NSArray *assets, BOOL isSelectOriginalPhoto) {

_fileArr = photos;

NSString *webImg =[NSString stringWithFormat:@"[""];

for (int i=0; i<photos.count; i++) {

// [self htmlForJPGImage:photos[i]] webImg =[webImg stringByAppendingString:[self htmlForJPGImage:photos[i]]]; webImg = [webImg stringByAppendingString:@"""];

if (i != photos.count - 1) { webImg = [webImg stringByAppendingString:@",""];

}

else {

webImg = [webImg stringByAppendingString:@"]"];

} }

NSLog(@"%@",webImg);

[self evaluateJsCode:callback val:webImg webview:self.webview];

}];`

想问下改写成 swift3 应该怎么写？