docs: def iter_tree_with_handed_function(self, function, *function_args):
          """Iterate tree view with condition check function"""
          def iter_all_children(row_iter, function, function_args):
              if isinstance(row_iter, Gtk.TreeIter):
                  function(row_iter, *function_args)
                  for n in reversed(range(self.tree_store.iter_n_children(row_iter))):
                      child_iter = self.tree_store.iter_nth_child(row_iter, n)
                      iter_all_children(child_iter, function, function_args)
              else:
                  self._logger.warning("Iter has to be TreeIter -> handed argument is: {0}".format(row_iter))
  
          # iter on root level of tree
          next_iter = self.tree_store.get_iter_first()
          while next_iter:
              iter_all_children(next_iter, function, function_args)
              next_iter = self.tree_store.iter_next(next_iter)