Nil tricks

then: Passes self to the given callable and passes along its return value. This is handy combined with &., e.g.:
```
s&.then(&Time.method(:parse))
```
You will get a nil if s is nil, otherwise you'll get Time.parse(s).
o.(): This is a synonym for o.call(). I don't know why you'd prefer the terse way but I worked with someone once who loved to write this everywhere.