let dict1 : [String:Int] = ["swift": 7, "java": 3, "c": 1, "c#": 2]
let dict2 : [String:Int] = ["pyton": 9, "c++": 7, "dart": 8]
let merge = dict1.merging(dict2) { (_, new) in new }
print(merge)
/*
run:
["pyton": 9, "c": 1, "c#": 2, "c++": 7, "java": 3, "swift": 7, "dart": 8]
*/