code: def _assertIntegral(self, sample_vals, pdf_vals, err=1e-3):
      s_p = zip(sample_vals, pdf_vals)
      prev = (0, 0)
      total = 0
      for k in sorted(s_p, key=lambda x: x[0]):
          pair_pdf = (k[1] + prev[1]) / 2
          total += (k[0] - prev[0]) * pair_pdf
          prev = k
      self.assertNear(1.0, total, err=err)
  
imports: import numpy
  from scipy import stats
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import kullback_leibler
  from tensorflow_probability.python.distributions import laplace
  from tensorflow_probability.python.internal import samplers
  from tensorflow_probability.python.internal import test_util
  from tensorflow_probability.python.math import gradient
label_desc: Use image node_id 19 for calling the LaplaceTest obj's underlying member method code with example usage: obj._assertIntegral(sample_vals, pdf_vals, err) without return types