code: def gamma_corr(clip, gamma):
      """Gamma-correction of a video clip."""
  
      def filter(im):
          corrected = 255 * (1.0 * im / 255) ** gamma
          return corrected.astype("uint8")
  
      return clip.image_transform(filter)
  
label_desc: Use image node_id 1 for calling a global function with example usage: gamma_corr(clip, gamma) and returns: clip, corrected