`else` clause is not necessary. `nil` will be an empty string when it's interpolated.

```ruby
$ irb
irb(main):001:0> def f
irb(main):002:1>   if false
irb(main):003:2>     'a'
irb(main):004:2>   end
irb(main):005:1> end
=> nil
irb(main):006:0> o = f
=> nil
irb(main):007:0> puts "bundle #{o}"
bundle 
=> nil
```