One must check Obj.key1, Obj.key2, ..., Obj.key(n-1) if they're undefined.

The normal convention would be:

```
if (typeof Obj !== 'undefined') {
  if (typeof Obj.key1 !== 'undefined') {
    if (typeof Obj.key1.key2 !== 'undefined')
      ...
        if (typeof Obj.key1.key2...keyN !== 'undefined') {
          return Obj.key1.key2...keyN
        }
      ...
    }
  }
}

```