Experiment: Fix return type annotation, remove unused type arguments

tianshou/highlevel/experiment.py

@@ -4,7 +4,7 @@ from abc import abstractmethod
 from collections.abc import Callable, Sequence
 from dataclasses import dataclass
 from pprint import pformat
-from typing import Any, Generic, Self, TypeVar
+from typing import Any, Self
 
 import numpy as np
 import torch
@@ -78,14 +78,11 @@ from tianshou.highlevel.trainer import (
 )
 from tianshou.highlevel.world import World
 from tianshou.policy import BasePolicy
-from tianshou.trainer import BaseTrainer
 from tianshou.utils import LazyLogger, logging
 from tianshou.utils.logging import datetime_tag
 from tianshou.utils.string import ToStringMixin
 
 log = logging.getLogger(__name__)
-TPolicy = TypeVar("TPolicy", bound=BasePolicy)
-TTrainer = TypeVar("TTrainer", bound=BaseTrainer)
 
 
 @dataclass
@@ -124,7 +121,7 @@ class ExperimentResult:
     """dictionary of results as returned by the trained (if any)"""
 
 
-class Experiment(Generic[TPolicy, TTrainer], ToStringMixin):
+class Experiment(ToStringMixin):
     """Represents a reinforcement learning experiment.
 
     An experiment is composed only of configuration and factory objects, which themselves
@@ -152,7 +149,7 @@ class Experiment(Generic[TPolicy, TTrainer], ToStringMixin):
         self.env_config = env_config
 
     @classmethod
-    def from_directory(cls, directory: str, restore_policy: bool = True) -> Self:
+    def from_directory(cls, directory: str, restore_policy: bool = True) -> "Experiment":
         """Restores an experiment from a previously stored pickle.
 
         :param directory: persistence directory of a previous run, in which a pickled experiment is found