code: def from_json(record_type, json_struct):
      
      if issubclass(record_type, JsonRecord):
          return record_type(json_struct)
  
      elif issubclass(record_type, Record):
          # do what the default JsonRecord __init__ does
          init_kwargs = json_to_initkwargs(record_type, json_struct)
          instance = record_type(**init_kwargs)
          return instance
      else:
          raise exc.CastTypeError(badtype=record_type)
docs: JSON marshall in function: a 'visitor' function which looks for JSON
      types/hints on types being converted to, but does not require them.
  
      Args:
          ``record_type=``\ *TYPE*
              Record type to convert data to
  
          ``json_struct=``\ *DICT|LIST*
              a loaded (via ``json.loads``) data structure, normally a
              dict or a list.