Just poking my nose in here, but I usually like `Array(node['postgresql']['wal_e']['packages']).each ...`

```ruby
1.9.3-p484 :001 > Array(nil)
 => []
1.9.3-p484 :002 > Array([])
 => []
1.9.3-p484 :003 > Array([:foo])
 => [:foo]
```

Carry on...