Method __init_subclass__

example_code/item_065.py:222–227

(cls)

print("Example 13")
class DescriptorRowMapper(RowMapper):
    def __init_subclass__(cls):
        fields = []
        for key, value in cls.__dict__.items():
            if isinstance(value, Field):  # Changed
                fields.append(key)
        cls.fields = tuple(fields)

try:
    DescriptorRowMapper.from_row([1, 2, 3, 4])