class_docstr: Gamma Distribution.
  
  Args:
      k(:class:`~chainer.Variable` or :ref:`ndarray`): Parameter of
          distribution.
      theta(:class:`~chainer.Variable` or :ref:`ndarray`): Parameter of
          distribution.
code: def __init__(self, k, theta):
      super(Gamma, self).__init__()
      self.__k = k
      self.__theta = theta
  
imports: import chainer
  from chainer.backends import cuda
  from chainer import distribution
  from chainer.functions.array import broadcast
  from chainer.functions.array import where
  from chainer.functions.math import digamma
  from chainer.functions.math import exponential
  from chainer.functions.math import lgamma
  from chainer.utils import cache
label_desc: Use image node_id 1 to create a new Gamma object from inherited base classes: distribution with example: obj = Gamma(k, theta)