code: def _assertIntegral(self, sample_vals, pdf_vals, err=1.5e-3):
      s_p = zip(sample_vals, pdf_vals)
      prev = (sample_vals.min() - 1000, 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 importlib
  import math
  import numpy
  from tensorflow.python.eager import backprop
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import random_seed
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import nn_ops
  from tensorflow.python.ops.distributions import student_t
  from tensorflow.python.platform import test
  from tensorflow.python.platform import tf_logging
label_desc: Use image node_id 23 for calling the StudentTTest obj's underlying member method code with example usage: obj._assertIntegral(sample_vals, pdf_vals, err) without return types