.DictItems: ClassType
.DictKeys: ClassType
.DictValues: ClassType

.Dict: ClassType
.Dict.
    copy: |D <: .Dict|(self: D) -> D
    fromkeys: |K, V| (iterable: Iterable K, value: V := NoneType) -> .Dict K, V
    get: |K, V, Default|(self: .Dict(K, V), key: K, default: Default := NoneType) -> V or Default
    items: |K, V|(self: .Dict(K, V)) -> .DictItems(K, V)
    keys: |K, V|(self: .Dict(K, V)) -> .DictKeys(K, V)
    values: |K, V|(self: .Dict(K, V)) -> .DictValues(K, V)
    '''erg
    dic = {"a": 1, "b": 2}
    assert dic.concat({"c": 3}) == {"a": 1, "b": 2, "c": 3}
    '''
    concat: (self: .Dict(K, V), other: .Dict(K, V)) -> .Dict(K, V)
    '''erg
    dic = {"a": 1, "b": 2}
    assert dic.diff({"a": 2, "d": 4}) == {"b": 2}
    '''
    diff: (self: .Dict(K, V), other: .Dict(K, V)) -> .Dict(K, V)