No, it's there because defining `singleton_method_added` triggers its own callback when defined:

```
➜ irb
irb(main):001:0> k = Object.new
=> #<Object:0x007ff6cb8bfed8>
irb(main):002:0> def k.singleton_method_added(name)
irb(main):003:1> puts name
irb(main):004:1> end
singleton_method_added
=> nil
```