def update(self, kalman_filter, detection):
        """
        Perform Kalman filter measurement update step and update the associated
        detection feature cache.
        """
        self.mean, self.covariance = kalman_filter.update(self.mean,
                                                          self.covariance,
                                                          detection.to_xyah())
        self.features.append(detection.feature)
        self.feat = detection.feature
        self.cls_id = detection.cls_id
        self.score = detection.score

        self.hits += 1
        self.time_since_update = 0
        if self.state == TrackState.Tentative and self.hits >= self._n_init:
            self.state = TrackState.Confirmed

        Perform Kalman filter measurement update step and update the associated
        detection feature cache.
        
ppdet/modeling/mot/tracker/base_sde_tracker.py