mob
    Login()
        var/list/list = list("a" = 1, "b" = 2, "c" = 3)
        list.RemoveAll("b")
        src << {"[json_encode(list)] should be {"a":1,"c":3}"} // it is
        src << "["b" in list] should be 0" // it is
        src << "[json_encode(list["b"])] should be null" // it's 2