Class A is writen in Objective C and have a custom init fucntion

```
@interface A ()

....

@end

@implementation A

- (id)customInitImplementedInA
{
    ... 
    return self;
}

```

Class B inherits from Class A and uses this custom init in the following way:

```
@interface B : A ()

....

@end

@implementation B
+(instancetype)instanceB{
    B *b = [[B alloc] customInitImplementedInA];
    ...
    return b;
}

```

Now I would like to create class C writen in **Swift** that inharits from A and uses the same init function. How do I do that? 

```
class C: A {
  //How do I use customInitImplementedInA here?
}

```