Gloabal normlizer 

class Model:
    def __init__(self, env, replay_pool, predict_reward=False, normalize_change=False):
        self.env = env
        self.replay_pool = replay_pool
        self.
        if not self.predict_reward 

        

    def predict(self, normalize_input_obs, normalize_input_action, unnormalize_output_obs, unnormalize_output_reward):

    def predict_np(self, normalize_input_obs, normalize_input_action, unnormalize_output_obs, unnormalize_output_reward):

    def fit():
        
    def get_diagnostics():

