code: def adjust_saturation(img, saturation_factor):
      """Adjust color saturation of an image.
  
      Args:
          img (PIL Image): PIL Image to be adjusted.
          saturation_factor (float):  How much to adjust the saturation. 0 will
              give a black and white image, 1 will give the original image while
              2 will enhance the saturation by a factor of 2.
  
      Returns:
          PIL Image: Saturation adjusted image.
      """
      if not _is_pil_image(img):
          raise TypeError(
              "img should be PIL Image. Got {}".format(type(img))
          )
  
      enhancer = ImageEnhance.Color(img)
      img = enhancer.enhance(saturation_factor)
      return img
  
imports: import random
  import os
  import math
  import mmcv
  import torch
  import numpy
  import torchvision.transforms
  from torchvision import datasets
  from torch.utils.data import Dataset
  from megatron import print_rank_0
  from megatron import get_args
  from PIL import Image, ImageOps, ImageEnhance
  import torchvision.transforms
label_desc: Use image node_id 4 for calling a global function with example usage: adjust_saturation(img, saturation_factor) and returns: img