code: def test_sample_neighbors_prob():
      _test_sample_neighbors(False, "prob", False)
      if (
          F._default_context_str != "gpu"
          and F.backend_name == "pytorch"
      ):
          _test_sample_neighbors(False, "prob", True)
  
imports: import unittest
  import warnings
  import backend
  import dgl
  import numpy
  import pytest
label_desc: Use image node_id 16 for calling a global function with example usage: test_sample_neighbors_prob() without return types