code: def log_images(self, name, images, step=None):
          
          if isinstance(images, six.string_types):
              raise TypeError('"images" should be a list of ndarrays, got {}'
                              .format(type(images)))
  
          self._check_step(step)
          tf_name = self._ensure_tf_name(name)
  
          summary = self._image_summary(tf_name, images, step=step)
          self._log_summary(tf_name, summary, images, step=step)
docs: Log new images for given name on given step.
  
          Args:
              name (str): name of the variable (it will be converted to a valid
                  tensorflow summary name).
              images (list): list of images to visualize
              step (int): non-negative integer used for visualization