using the following simplified structure:

```
class Property: Mappable {
    var path: String?

    override func mapping(map: Map) {
        path <- map["path"]
    }
}

class Specification {
    enum Name: String {
        case Small = "SMALL"
        case Medium = "MEDIUM"
    }
}

class ItemWithImages: Mappable {
    var properties: [Specification.Name : Property]?

    override func mapping(map: Map) {
        properties <- (map["properties"], EnumTransform<Specification.Name>())
    }
}

```

... with that JSON:

```
[{"properties: ["SMALL": {"path": "http://..."}, "MEDIUM": {"path": "http://..."}]}]

```

... produces when using EnumTransform() as Transform the following (reasonable) compile error:

```
Binary operator '<-' cannot be applied to operands of type '[Specification.Name : Property]?' and '(Map, EnumTransform<Specification.Name>)'

```

So how does a custom TransformType have to look like, to map that dictionary the right way? 

You can find the source of EnumTransform here: <https://github.com/Hearst-DD/ObjectMapper/blob/master/ObjectMapper/Transforms/EnumTransform.swift>

Thanks!