import abc
from collections.abc import Iterator, Iterable
import io
from typing import Protocol, TypeVar

T = TypeVar("T")

class CheckpointableIterator(Iterator[T], Protocol[T]):
  pass

isinstance(io.TextIOBase, Iterable)

from flax import linen as nn

class Steppable(metaclass=abc.ABCMeta):
  path: str

class SequenceLayer(nn.Module, Steppable):
  pass

Traceback (most recent call last):
  File "/usr/local/google/home/phawkins/p/flax/t.py", line 21, in <module>
    class SequenceLayer(nn.Module, Steppable):
  File "<frozen abc>", line 106, in __new__
  File "/usr/local/google/home/phawkins/p/flax/flax/linen/module.py", line 1040, in __init_subclass__
    cls._customized_dataclass_transform(kw_only)
  File "/usr/local/google/home/phawkins/p/flax/flax/linen/module.py", line 1100, in _customized_dataclass_transform
    dataclasses.dataclass(  # type: ignore[call-overload]
  File "/usr/local/google/home/phawkins/.local/share/uv/python/cpython-3.12.10-linux-x86_64-gnu/lib/python3.12/dataclasses.py", line 1265, in wrap
    return _process_class(cls, init, repr, eq, order, unsafe_hash,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/google/home/phawkins/.local/share/uv/python/cpython-3.12.10-linux-x86_64-gnu/lib/python3.12/dataclasses.py", line 1018, in _process_class
    raise TypeError(f'{name!r} is a field but has no type annotation')
TypeError: 'parent' is a field but has no type annotation

    setattr(cls, '__annotations__', cls.__annotations__)

    dataclasses.dataclass(  # type: ignore[call-overload]
      unsafe_hash='__hash__' not in cls.__dict__,
      repr=False,
      kw_only=kw_only,
    )(cls)