class_docstr: Randomly adjust gamma 
class_docstr_tok: ["Randomly","adjust","gamma"]
code: def _augment(self, img, gamma):
      old_dtype = img.dtype
      lut = (
          (np.arange(256, dtype="float32") / 255)
          ** (1.0 / (1.0 + gamma))
          * 255
      ).astype("uint8")
      img = np.clip(img, 0, 255).astype("uint8")
      ret = cv2.LUT(img, lut).astype(old_dtype)
      if img.ndim == 3 and ret.ndim == 2:
          ret = ret[:, :, np.newaxis]
      return ret
  
imports: import numpy
  import cv2
  from ...utils.develop import log_deprecated
  from .base import PhotometricAugmentor
label_desc: Use image node_id 3 for calling the Gamma obj's underlying member method code with example usage: obj._augment(img, gamma) and returns: ret