def __init__()

in rlmeta/envs/atari_wrappers.py [0:0]


    def __init__(self,
                 env,
                 width=84,
                 height=84,
                 grayscale=True,
                 dict_space_key=None):
        """
        Warp frames to 84x84 as done in the Nature paper and later work.

        If the environment uses dictionary observations, `dict_space_key` can be
        specified which indicates which observation should be warped.
        """
        super().__init__(env)
        self._width = width
        self._height = height
        self._grayscale = grayscale
        self._key = dict_space_key
        if self._grayscale:
            num_colors = 1
        else:
            num_colors = 3

        new_space = gym.spaces.Box(
            low=0,
            high=255,
            shape=(self._height, self._width, num_colors),
            dtype=np.uint8,
        )
        if self._key is None:
            original_space = self.observation_space
            self.observation_space = new_space
        else:
            original_space = self.observation_space.spaces[self._key]
            self.observation_space.spaces[self._key] = new_space
        assert original_space.dtype == np.uint8 and len(
            original_space.shape) == 3