<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _read_depth_images(self, num_images):
 """ Reads depth images from the device """

        depth_images = self._ros_read_images(self._depth_image_buffer, num_images, self.staleness_limit)
        for i in range(0, num_images):
            depth_images[i] = depth_images[i] * MM_TO_METERS # convert to meters
            if self._flip_images:
                depth_images[i] = np.flipud(depth_images[i])
                depth_images[i] = np.fliplr(depth_images[i])
            depth_images[i] = DepthImage(depth_images[i], frame=self._frame) 
        return depth_images