diff --git a/cirq-core/cirq/protocols/json_serialization.py b/cirq-core/cirq/protocols/json_serialization.py index ca41e6e040b..c9ffea4c1d3 100644 --- a/cirq-core/cirq/protocols/json_serialization.py +++ b/cirq-core/cirq/protocols/json_serialization.py @@ -584,8 +584,8 @@ def to_json( obj: Any, file_or_fn: Union[None, IO, pathlib.Path, str] = None, *, - indent: int = 2, - separators: Tuple[str, str] = None, + indent: Optional[int] = 2, + separators: Optional[Tuple[str, str]] = None, cls: Type[json.JSONEncoder] = CirqEncoder, ) -> Optional[str]: """Write a JSON file containing a representation of obj.