test1: ---
assert(listOf("Hello", "World")[1] == "Hello")
       |                       |   |
       |                       |   false
       |                       World
       [Hello, World]
---
test2: ---
assert(listOf("Hello", "World").get(1) == "Hello")
       |                        |      |
       |                        |      false
       |                        World
       [Hello, World]
---
test3: ---
assert(map["key3"] == 300)
       |  |        |
       |  |        false
       |  null
       {key1=100, key2=200}
---
test4: ---
assert(matrix[0, 1] == 99)
       |     |      |
       |     |      false
       |     2
       [[1, 2, 3]]
---
