code: def contrast(image, factor):
      """Equivalent of PIL Contrast."""
      degenerate = tf.image.rgb_to_grayscale(image)
      # Cast before calling tf.histogram.
      degenerate = tf.cast(degenerate, tf.int32)
  
      # Compute the grayscale histogram, then compute the mean pixel value,
      # and create a constant image size of that value.  Use that as the
      # blending degenerate target of the original image.
      hist = tf.histogram_fixed_width(degenerate, [0, 255], nbins=256)
      mean = tf.reduce_sum(tf.cast(hist, tf.float32)) / 256.0
      degenerate = tf.ones_like(degenerate, dtype=tf.float32) * mean
      degenerate = tf.clip_by_value(degenerate, 0.0, 255.0)
      degenerate = tf.image.grayscale_to_rgb(
          tf.cast(degenerate, tf.uint8)
      )
      return blend(degenerate, image, factor)
  
imports: import dataclasses
  import inspect
  import math
  import tensorflow.compat.v1
  from tensorflow_addons import image
label_desc: Use image node_id 8 for calling a global function with example usage: contrast(image, factor) and returns: blend