class_docstr: Adjust image contrast by scaling pixel values to ``255*((v/255)**gamma)``.
  
  Values in the range ``gamma=(0.5, 2.0)`` seem to be sensible.
  
  **Supported dtypes**:
  
  See :func:`~imgaug.augmenters.contrast.adjust_contrast_gamma`.
  
  Parameters
  ----------
  gamma : number or tuple of number or list of number or imgaug.parameters.StochasticParameter, optional
      Exponent for the contrast adjustment. Higher values darken the image.
  
          * If a number, then that value will be used for all images.
          * If a tuple ``(a, b)``, then a value from the range ``[a, b]``
            will be used per image.
          * If a list, then a random value will be sampled from that list
            per image.
          * If a ``StochasticParameter``, then a value will be sampled per
            image from that parameter.
  
  per_channel : bool or float, optional
      Whether to use the same value for all channels (``False``) or to
      sample a new value for each channel (``True``). If this value is a
      float ``p``, then for ``p`` percent of all images `per_channel` will
      be treated as ``True``, otherwise as ``False``.
  
  seed : None or int or imgaug.random.RNG or numpy.random.Generator or numpy.random.BitGenerator or numpy.random.SeedSequence or numpy.random.RandomState, optional
      See :func:`~imgaug.augmenters.meta.Augmenter.__init__`.
  
  name : None or str, optional
      See :func:`~imgaug.augmenters.meta.Augmenter.__init__`.
  
  random_state : None or int or imgaug.random.RNG or numpy.random.Generator or numpy.random.BitGenerator or numpy.random.SeedSequence or numpy.random.RandomState, optional
      Old name for parameter `seed`.
      Its usage will not yet cause a deprecation warning,
      but it is still recommended to use `seed` now.
      Outdated since 0.4.0.
  
  deterministic : bool, optional
      Deprecated since 0.4.0.
      See method ``to_deterministic()`` for an alternative and for
      details about what the "deterministic mode" actually does.
  
  Examples
  --------
  >>> import imgaug.augmenters as iaa
  >>> aug = iaa.GammaContrast((0.5, 2.0))
  
  Modify the contrast of images according to ``255*((v/255)**gamma)``,
  where ``v`` is a pixel value and ``gamma`` is sampled uniformly from
  the interval ``[0.5, 2.0]`` (once per image).
  
  >>> aug = iaa.GammaContrast((0.5, 2.0), per_channel=True)
  
  Same as in the previous example, but ``gamma`` is sampled once per image
  *and* channel.
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code: def __init__(
      self,
      gamma=(0.7, 1.7),
      per_channel=False,
      seed=None,
      name=None,
      random_state="deprecated",
      deterministic="deprecated",
  ):
      params1d = [
          iap.handle_continuous_param(
              gamma,
              "gamma",
              value_range=None,
              tuple_to_uniform=True,
              list_to_choice=True,
          )
      ]
      func = adjust_contrast_gamma
      super(GammaContrast, self).__init__(
          func,
          params1d,
          per_channel,
          dtypes_allowed="uint8 uint16 uint32 uint64 int8 int16 int32 int64 "
          "float16 float32 float64",
          dtypes_disallowed="float128 bool",
          seed=seed,
          name=name,
          random_state=random_state,
          deterministic=deterministic,
      )
  
imports: from __future__ import print_function, division, absolute_import
  import numpy
  import six.moves
  import skimage.exposure
  import cv2
  import imgaug
  from imgaug.imgaug import _normalize_cv2_input_arr_
  from .None import meta
  from .None import color
  from ..None import parameters
  from ..None import dtypes
  from ..augmentables.batches import _BatchInAugmentation
label_desc: Use image node_id 1 to create a new GammaContrast object from inherited base classes: _ContrastFuncWrapper with example: obj = GammaContrast(gamma, per_channel, seed, name, random_state, deterministic)