from tensorflow.contrib.distributions.python.ops import distribution_util


  @distribution_util.AppendDocstring(_poisson_sample_note)
  def _log_cdf(self, x):
    return math_ops.log(self.cdf(x))

  @distribution_util.AppendDocstring(_poisson_sample_note)
  def _cdf(self, x):
    x = self._assert_valid_sample(x, check_integer=False)
    return math_ops.igammac(math_ops.floor(x + 1), self.rate)

