Modernize type annotations in in_memory_backend.py and riegeli_backend_writer.py.

envlogger/backends/in_memory_backend.py

@@ -17,7 +17,7 @@
 """
 
 import copy
-from typing import Any
+from typing import Any, Self
 
 from envlogger import step_data
 from envlogger.backends import backend_reader
@@ -57,7 +57,7 @@ def __init__(self, in_memory_backend_writer: InMemoryBackendWriter):
     self._backend = in_memory_backend_writer
     super().__init__()
 
-  def _copy(self) -> 'InMemoryBackendReader':
+  def _copy(self) -> Self:
     return copy.deepcopy(self)
 
   def close(self) -> None:

envlogger/backends/riegeli_backend_writer.py

@@ -16,7 +16,7 @@
 """For writing trajectory data to riegeli files."""
 
 import datetime
-from typing import Any, Optional
+from typing import Any
 
 from absl import logging
 from envlogger import step_data
@@ -35,7 +35,7 @@ def __init__(
       data_directory: str,
       max_episodes_per_file: int = 10000,
       writer_options: str = 'transpose,brotli:6,chunk_size:1M',
-      flush_scheduler: Optional[schedulers.Scheduler] = None,
+      flush_scheduler: schedulers.Scheduler | None = None,
       **base_kwargs,
   ):
     """Constructor.