How about testing with more nesting levels and also in 2d arrays? e.g.

string

```ruby
{
  'a' => 'b',
  'nested_hash' => { 'c' => 'd' },
  'nested_array' => [{ 'g' => [{ 'h' => 'i' }] }, [{ 'j' => [{ 'k' => [[{ 'l' => 'm' }]] }] }]]
}
```

symbol

```ruby
{
  :a => 'b',
  :nested_hash => { :c => 'd' },
  :nested_array => [{ :g => [{ :h => 'i' }] }, [{ :j => [{ :k => [[{ :l => 'm' }]] }] }]]
}
```