Functions

1. Functions and methods
2. Function return value
3. Function parameter passing
4. Function parameter default value
5. Wrong number of arguments
6. Any number of arguments (splat, *)
7. Manually separate
8. Tuple from
9. Array overload
10. Multiple dispatch
11. Implicit return value
12. Return Type definition
13. Type or Nil
14. Yield
15. Yield with parameters
16. Block and parameters