Before:
root
|-- a: struct (nullable = true)
| |-- b: string (nullable = true)
| |-- c: array (nullable = true)
| | |-- element: struct (containsNull = true)
| | | |-- d: array (nullable = true)
| | | | |-- element: string (containsNull = true)
| | | |-- e: string (nullable = true)