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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def compare_variables(tree_model, iter1, iter2, user_data=None):
 """Triggered upon updating the list of global variables Helper method to sort global variables alphabetically. :param tree_model: Tree model implementing the Gtk.TreeSortable interface. :param iter1: Points at a row. :param iter2: Points at a row. """

        path1 = tree_model.get_path(iter1)[0]
        path2 = tree_model.get_path(iter2)[0]
        # get key of first variable
        name1 = tree_model[path1][0]
        # get key of second variable
        name2 = tree_model[path2][0]
        name1_as_bits = ' '.join(format(ord(x), 'b') for x in name1)
        name2_as_bits = ' '.join(format(ord(x), 'b') for x in name2)
        if name1_as_bits == name2_as_bits:
            return 0
        elif name1_as_bits > name2_as_bits:
            return 1
        else:
            return -1