code: def setUp(self):
      self.model_data = {
          "description": "",
          "discount": "0.95",
          "variables": {
              "StateVar": [
                  {
                      "vnamePrev": "rover_0",
                      "vnameCurr": "rover_1",
                      "ValueEnum": ["s0", "s1", "s2"],
                      "fullyObs": True,
                  },
                  {
                      "vnamePrev": "rock_0",
                      "vnameCurr": "rock_1",
                      "fullyObs": False,
                      "ValueEnum": ["good", "bad"],
                  },
              ],
              "ObsVar": [
                  {
                      "vname": "obs_sensor",
                      "ValueEnum": ["ogood", "obad"],
                  }
              ],
              "RewardVar": [{"vname": "reward_rover"}],
              "ActionVar": [
                  {
                      "vname": "action_rover",
                      "ValueEnum": ["amw", "ame", "ac", "as"],
                  }
              ],
          },
          "initial_state_belief": [
              {
                  "Var": "rover_0",
                  "Parent": ["null"],
                  "Type": "TBL",
                  "Parameter": [
                      {
                          "Instance": ["-"],
                          "ProbTable": ["0.0", "1.0", "0.0"],
                      }
                  ],
              },
              {
                  "Var": "rock_0",
                  "Parent": ["null"],
                  "Type": "TBL",
                  "Parameter": [
                      {"Instance": ["-"], "ProbTable": ["uniform"]}
                  ],
              },
          ],
          "state_transition_function": [
              {
                  "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"],
                      },
                  ],
              },
          ],
          "obs_function": [
              {
                  "Var": "obs_sensor",
                  "Parent": ["action_rover", "rover_1", "rock_1"],
                  "Type": "TBL",
                  "Parameter": [
                      {
                          "Instance": ["amw", "*", "*", "-"],
                          "ProbTable": ["1.0", "0.0"],
                      },
                      {
                          "Instance": ["ame", "*", "*", "-"],
                          "ProbTable": ["1.0", "0.0"],
                      },
                      {
                          "Instance": ["as", "*", "*", "-"],
                          "ProbTable": ["1.0", "0.0"],
                      },
                      {
                          "Instance": ["ac", "s0", "-", "-"],
                          "ProbTable": ["1.0", "0.0", "0.0", "1.0"],
                      },
                      {
                          "Instance": ["ac", "s1", "-", "-"],
                          "ProbTable": ["0.8", "0.2", "0.2", "0.8"],
                      },
                      {
                          "Instance": ["ac", "s2", "*", "-"],
                          "ProbTable": ["1.0", "0.0"],
                      },
                  ],
              }
          ],
          "reward_function": [
              {
                  "Var": "reward_rover",
                  "Parent": ["action_rover", "rover_0", "rock_0"],
                  "Type": "TBL",
                  "Parameter": [
                      {
                          "Instance": ["ame", "s1", "*"],
                          "ValueTable": ["10"],
                      },
                      {
                          "Instance": ["amw", "s0", "*"],
                          "ValueTable": ["-100"],
                      },
                      {
                          "Instance": ["as", "s1", "*"],
                          "ValueTable": ["-100"],
                      },
                      {
                          "Instance": ["as", "s0", "good"],
                          "ValueTable": ["10"],
                      },
                      {
                          "Instance": ["as", "s0", "bad"],
                          "ValueTable": ["-10"],
                      },
                  ],
              }
          ],
      }
  
      self.writer = PomdpXWriter(model_data=self.model_data)
  
imports: import io
  import sys
  import unittest
  import xml.etree.ElementTree
  from pgmpy.readwrite import PomdpXReader, PomdpXWriter
label_desc: Use image node_id 1 for calling the TestPomdpXWriterTorch obj's underlying member method code with example usage: obj.setUp() without return types