code: def test_sample_lam_random(self, beta):
      mm = ManifoldMixup()
      sl = mm._sample_lam
      sl()
  
      self.assertTrue(beta.mock_calls[0][1] == (1.0, 1.0))
      self.assertTrue(beta.mock_calls[1][0] == "().sample")
  
imports: from unittest import TestCase
  from mock import patch, Mock
  from torch import nn
  from torchbearer.callbacks.manifold_mixup import ManifoldMixup
  import torchbearer
  import torch
label_desc: Use image node_id 15 for calling the TestManifoldMixup obj's underlying member method code with example usage: obj.test_sample_lam_random(beta) without return types