my.core.serialize: formatting fixes

my/core/serialize.py

@@ -25,7 +25,6 @@ def _default_encode(obj: Any) -> Any:
         return obj._asdict()
     if isinstance(obj, datetime.timedelta):
         return obj.total_seconds()
-
     if isinstance(obj, Exception):
         return error_to_json(obj)
     # note: _serialize would only be called for items which aren't already
@@ -142,7 +141,6 @@ def test_default_serializer() -> None:
     import pytest
     import json as jsn  # dont cause possible conflicts with module code
 
-
     class Unserializable:
         def __init__(self, x: int):
             self.x = x