gym序列化、EzPickle类

EzPickle是一个用于强化学习环境的类，它重写了__getstate__和__setstate__方法，以便通过构造函数参数(*args,**kwargs)进行序列化和反序列化。这个设计允许那些无法直接用pickle库处理的对象，如数据库连接和网络套接字，也能在保存和恢复时保持其状态。

"""Class for pickling and unpickling objects via their constructor arguments."""
from typing import Any


class EzPickle:
    """Objects that are pickled and unpickled via their constructor arguments.

    Example:
        >>> class Animal: pass
        >>> class Dog(Animal, EzPickle):
        ...    def __init__(self, furcolor, tailkind="bushy"):
        ...        Animal.__init__(self)
        ...        EzPickle.__init__(self, furcolor, tailkind)

    When this object is unpickled, a new ``Dog`` will be constructed by passing the provided furcolor and tailkind into the constructor.
    However, philosophers are still not sure whether it is still the same dog.

    This is generally needed only for environments which wrap C/C++ code, such as MuJoCo and Atari.
    """

    def __init__(self, *args: Any, **kwargs: Any):
        """Uses the ``args`` and ``kwargs`` from the object's constructor for pickling."""
        self._ezpickle_args = args
        self._ezpickle_kwargs = kwargs

    def __getstate__(self):
        """Returns the object pickle state with args and kwargs."""
        return {
            "_ezpickle_args": self._ezpickle_args,
            "_ezpickle_kwargs": self._ezpickle_kwargs,
        }

    def __setstate__(self, d):
        """Sets the object pickle state using d."""
        out = type(self)(*d["_ezpickle_args"], **d["_ezpickle_kwargs"])
        self.__dict__.update(out.__dict__)

    def __init__(
        self,
        forward_reward_weight=1.0,
        ctrl_cost_weight=0.1,
        reset_noise_scale=0.1,
        exclude_current_positions_from_observation=True,
        **kwargs,
    ):
        utils.EzPickle.__init__(
            self,
            forward_reward_weight,
            ctrl_cost_weight,
            reset_noise_scale,
            exclude_current_positions_from_observation,
            **kwargs,
        )