code: def duplicate_object_hook(ordered_pairs):
      
      json_dict = {}
      for key, val in ordered_pairs:
          existing_val = json_dict.get(key)
          if not existing_val:
              json_dict[key] = val
          else:
              if isinstance(existing_val, list):
                  existing_val.append(val)
              else:
                  json_dict[key] = [existing_val, val]
  
      return json_dict
docs: Make lists out of duplicate keys.