code: def testExponentialLogPDFBoundary(self):
      # Check that Log PDF is finite at 0.
      rate = np.array([0.1, 0.5, 1.0, 2.0, 5.0, 10.0], dtype=np.float32)
      dist = exponential.Exponential(rate=rate, validate_args=False)
      log_pdf = dist.log_prob(0.0)
      self.assertAllClose(np.log(rate), self.evaluate(log_pdf))
  
imports: import numpy
  from scipy import stats
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import exponential
  from tensorflow_probability.python.distributions import kullback_leibler
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.math import gradient
label_desc: Use image node_id 2 for calling the ExponentialTest obj's underlying member method code with example usage: obj.testExponentialLogPDFBoundary() without return types