code: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  
  import tensorflow as tf
  
  
  
  def data_augmentation(image, is_training=None):
      
      if is_training:
          return preprocess_for_train(image)
      
      else:
          return preprocess_for_eval(image)
      
     
      
  def preprocess_for_train(image):
      #distorted_image = tf.image.random_brightness(image, max_delta=63)!!!Is nothing after random_brightness
      distorted_image = tf.image.random_contrast(image, lower=0.2, upper=1.8)
      return distorted_image
  def preprocess_for_eval(image):
      #distorted_image = tf.image.random_brightness(image, max_delta=63)!!!Is nothing after random_brightness
      distorted_image = tf.image.random_contrast(image, lower=0.2, upper=1.8)
      return distorted_image
      
apis: tensorflow.image.random_contrast