docs: def _update_tree_store(self):
          """ Updates TreeStore of the Gtk.ListView according internal combo knowledge gained by
          _update_internal_data_base function call.
          """
  
          self.list_store.clear()
          if self.view_dict['transitions_internal'] and isinstance(self.model, ContainerStateModel) and \
                  len(self.model.state.transitions) > 0:
              for transition_id in self.combo['internal'].keys():
                  # print("TRANSITION_ID: ", transition_id, self.model.state.transitions)
                  t = self.model.state.transitions[transition_id]
  
                  if t.from_state is not None:
                      from_state = self.model.state.states[t.from_state]
                      from_state_label = from_state.name
                      from_outcome_label = from_state.outcomes[t.from_outcome].name
                  else:
                      from_state_label = "self (" + self.model.state.name + ")"
                      from_outcome_label = ""
  
                  if t.to_state is None:
                      to_state_label = "self (" + self.model.state.name + ")"
                      to_outcome = None if t.to_outcome is None else self.model.state.outcomes[t.to_outcome]
                      to_outcome_label = "None" if to_outcome is None else to_outcome.name
                  else:
                      # print(t.to_state, self.model.states)
                      if t.to_state == self.model.state.state_id:
                          to_state_label = "self (" + self.model.state.name + ")"
                          to_outcome_label = self.model.state.outcomes[t.to_outcome].name
                      else:
                          to_state_label = self.model.state.states[t.to_state].name
                          to_outcome_label = None
  
                  self.list_store.append([transition_id,  # id
                                          from_state_label,  # from-state
                                          from_outcome_label,  # from-outcome
                                          to_state_label,  # to-state
                                          to_outcome_label,  # to-outcome
                                          False,  # is_external
                                          t,
                                          self.model.state,
                                          True,
                                          self.model.get_transition_m(transition_id)])
  
          if self.view_dict['transitions_external'] and self.model.parent and \
                  len(self.model.parent.state.transitions) > 0:
              for transition_id in self.combo['external'].keys():
                  # print("TRANSITION_ID: ", transition_id, self.model.parent.state.transitions)
                  try:
                      t = self.model.parent.state.transitions[transition_id]
                      # logger.info(str(t))
                      from_state = None
                      if t.from_state is not None:
                          from_state = self.model.parent.states[t.from_state].state
  
                      if from_state is None:
                          from_state_label = "parent (" + self.model.state.parent.name + ")"
                          from_outcome_label = ""
                      elif from_state.state_id == self.model.state.state_id:
                          from_state_label = "self (" + from_state.name + ")"
                          from_outcome_label = from_state.outcomes[t.from_outcome].name
                      else:
                          from_state_label = from_state.name
                          from_outcome_label = from_state.outcomes[t.from_outcome].name
  
                      if t.to_state == self.model.parent.state.state_id:
                          to_state_label = 'parent (' + self.model.parent.state.name + ")"
                          to_outcome_label = self.model.parent.state.outcomes[t.to_outcome].name
                      else:
                          if t.to_state == self.model.state.state_id:
                              to_state_label = "self (" + self.model.state.name + ")"
                          else:
                              to_state_label = self.model.parent.state.states[t.to_state].name
                          to_outcome_label = None
  
                      self.list_store.append([transition_id,  # id
                                              from_state_label,  # from-state
                                              from_outcome_label,  # from-outcome
                                              to_state_label,  # to-state
                                              to_outcome_label,  # to-outcome
                                              True,  # is_external
                                              t,
                                              self.model.state,
                                              True,
                                              self.model.parent.get_transition_m(transition_id)])
                  except Exception as e:
                      logger.warning("There was a problem while updating the data-flow widget TreeStore. {0}".format(e))