def print_models(unprinted_designs, completed_models):
    '''
    Имитирует печать моделей, пока список не станет пустым.
    Каждая модель после печати перемещается в completed_models.
    '''

    while unprinted_designs:
        current_design = unprinted_designs.pop()
        # Имитация печати модели на 3D-принтере.
        print('Printing model: ' + current_design)
        completed_models.append(current_design)

def show_completed_models(completed_models):
    '''Выводит информацию обо всех напечатанных моделях.'''
    print('\nThe following models have been printed:')
    for completed_model in completed_models:
        print(completed_model)

unprinted_designs = ['iphone case', 'robot pendant', 'dodecahedron']
completed_models = []
print_models(unprinted_designs[:], completed_models)
show_completed_models(completed_models)
print(unprinted_designs)