docs: def get_state_transition_function(self):
          """
          Returns the transition of the state variables as nested dict in the
          case of table type parameter and a nested structure in case of
          decision diagram parameter
  
          Example
          --------
          >>> reader = PomdpXReader('Test_PomdpX.xml')
          >>> reader.get_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']},
                           ...
                          ]
          }]
          """
          state_transition_function = []
          for variable in self.network.findall('StateTransitionFunction'):
              for var in variable.findall('CondProb'):
                  cond_prob = defaultdict(list)
                  cond_prob['Var'] = var.find('Var').text
                  cond_prob['Parent'] = var.find('Parent').text.split()
                  if not var.find('Parameter').get('type'):
                      cond_prob['Type'] = 'TBL'
                  else:
                      cond_prob['Type'] = var.find('Parameter').get('type')
                  cond_prob['Parameter'] = self.get_parameter(var)
                  state_transition_function.append(cond_prob)
  
          return state_transition_function