code: def normalize_output_field(field_data, field_def)
        return case field_data
          when Array
            normalize_array_field(field_data, field_def)
          when Hash
            normalize_hash_field(field_data, field_def)
          else
            normalize_item(field_data, field_def)
        end
      end
docs: Normalizes one field of a given data recursively.
  
   Args:
    - field_data: XML data to normalize
    - field_def: field type definition for the data