docs: def update_global_variables_list_store(self):
          """Updates the global variable list store
  
          Triggered after creation or deletion of a variable has taken place.
          """
          # logger.info("update")
          self.list_store_iterators = {}
          self.list_store.clear()
          keys = self.model.global_variable_manager.get_all_keys()
          keys.sort()
          for key in keys:
              iter = self.list_store.append([key,
                                             self.model.global_variable_manager.get_data_type(key).__name__,
                                             str(self.model.global_variable_manager.get_representation(key)),
                                             str(self.model.global_variable_manager.is_locked(key)),
                                             ])
              self.list_store_iterators[key] = iter