code: def apply_gradients(self, gradients):
      feed_dict = {}
      for i in range(len(self.grads_placeholder)):
          feed_dict[self.grads_placeholder[i][0]] = gradients[i]
      self.sess.run(self.apply_grads_placeholder, feed_dict=feed_dict)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import time
  import tensorflow
  from tensorflow.examples.tutorials.mnist import input_data
  import ray
  import ray.experimental.tf_utils
  from bigdl.dllib.utils.log4Error import invalidInputError
label_desc: Use image node_id 4 for calling the SimpleCNN obj's underlying member method code with example usage: obj.apply_gradients(gradients) without return types