Achievement Solution

var matchmakingIds: [Int] = []

for categoryDictionary in categoryDictionaries {
	
	if let title = categoryDictionary["title"] as? String, title == "Matchmaking"{


		guard let children = categoryDictionary["children"] as? [NSDictionary] else {
			print("Cannot find key 'children' in \(categoryDictionary)")
			return
		} 

		for child in children {
			guard let categoryId = child["categoryId"] as? Int else {
			 	print("Cannot find key 'categoryId' in \(child)")
			    return
			}
			matchmakingIds.append(categoryId)

		}
	}

}