code: def format_output(old_maps, new_maps):
          
  
          # if input is FieldArray then return FieldArray
          if isinstance(old_maps, record.FieldArray):
              keys = new_maps.keys()
              values = [new_maps[key] for key in keys]
              for key, vals in zip(keys, values):
                  try:
                      old_maps = old_maps.add_fields([vals], [key])
                  except ValueError:
                      old_maps[key] = vals
              return old_maps
  
          # if input is dict then return dict
          elif isinstance(old_maps, dict):
              out = old_maps.copy()
              out.update(new_maps)
              return out
  
          # else error
          else:
              raise TypeError("Input type must be FieldArray or dict.")
docs: This function takes the returned dict from `transform` and converts
          it to the same datatype as the input.
  
          Parameters
          ----------
          old_maps : {FieldArray, dict}
              The mapping object to add new maps to.
          new_maps : dict
              A dict with key as parameter name and value is numpy.array.
  
          Returns
          -------
          {FieldArray, dict}
              The old_maps object with new keys from new_maps.