def filter(self, observations: List[ObservationType], update_internal_state: bool=True) -> ObservationType:
    observations = np.array(observations)
    if update_internal_state:
        self.running_observation_stats.push(observations)
        self.last_mean = self.running_observation_stats.mean
        self.last_stdev = self.running_observation_stats.std
    return self.running_observation_stats.normalize(observations)
def filter(self, observations: List[ObservationType], update_internal_state: bool=True) -> ObservationType:
    observations = np.array(observations)
    if update_internal_state:
        self.running_observation_stats.push(observations)
        self.last_mean = self.running_observation_stats.mean
        self.last_stdev = self.running_observation_stats.std
    return self.running_observation_stats.normalize(observations)