code: def test_get_state_transition_function(self):
      state_transition_function_expected = [
          {
              "Var": "rover_1",
              "Parent": ["action_rover", "rover_0"],
              "Type": "TBL",
              "Parameter": [
                  {
                      "Instance": ["amw", "s0", "s2"],
                      "ProbTable": ["1.0"],
                  },
                  {
                      "Instance": ["amw", "s1", "s0"],
                      "ProbTable": ["1.0"],
                  },
                  {
                      "Instance": ["ame", "s0", "s1"],
                      "ProbTable": ["1.0"],
                  },
                  {
                      "Instance": ["ame", "s1", "s2"],
                      "ProbTable": ["1.0"],
                  },
                  {
                      "Instance": ["ac", "s0", "s0"],
                      "ProbTable": ["1.0"],
                  },
                  {
                      "Instance": ["ac", "s1", "s1"],
                      "ProbTable": ["1.0"],
                  },
                  {
                      "Instance": ["as", "s0", "s0"],
                      "ProbTable": ["1.0"],
                  },
                  {
                      "Instance": ["as", "s1", "s2"],
                      "ProbTable": ["1.0"],
                  },
                  {"Instance": ["*", "s2", "s2"], "ProbTable": ["1.0"]},
              ],
          },
          {
              "Var": "rock_1",
              "Parent": ["action_rover", "rover_0", "rock_0"],
              "Type": "TBL",
              "Parameter": [
                  {
                      "Instance": ["amw", "*", "-", "-"],
                      "ProbTable": ["1.0", "0.0", "0.0", "1.0"],
                  },
                  {
                      "Instance": ["ame", "*", "-", "-"],
                      "ProbTable": ["identity"],
                  },
                  {
                      "Instance": ["ac", "*", "-", "-"],
                      "ProbTable": ["identity"],
                  },
                  {
                      "Instance": ["as", "*", "-", "-"],
                      "ProbTable": ["identity"],
                  },
                  {
                      "Instance": ["as", "s0", "*", "-"],
                      "ProbTable": ["0.0", "1.0"],
                  },
              ],
          },
      ]
      self.maxDiff = None
      self.assertEqual(
          self.reader_string.get_state_transition_function(),
          state_transition_function_expected,
      )
      self.assertEqual(
          self.reader_file.get_state_transition_function(),
          state_transition_function_expected,
      )
  
imports: import io
  import sys
  import unittest
  import xml.etree.ElementTree
  from pgmpy.readwrite import PomdpXReader, PomdpXWriter
label_desc: Use image node_id 4 for calling the TestPomdpXReaderString obj's underlying member method code with example usage: obj.test_get_state_transition_function() without return types