---
assert(text == null || text.length == 1 || text.lowercase() == text)
       |    |          |    |      |       |    |           |  |
       |    |          |    |      |       |    |           |  Hello
       |    |          |    |      |       |    |           false
       |    |          |    |      |       |    hello
       |    |          |    |      |       Hello
       |    |          |    |      false
       |    |          |    5
       |    |          Hello
       |    false
       Hello
---
