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Extension
===============

.. toctree::
    :maxdepth: 1

    3.1.1_counting_device_c
    3.1.2_welcome_c
    3.1.3_reversing_alarm_c
    3.1.4_smart_fan_c
    3.1.5_battery_indicator_c
    3.1.6_traffic_light_c
    3.1.7_overheat_monitor_c
    3.1.8_password_lock_c
    3.1.9_alarm_bell_c
    3.1.10_morse_code_generator_c
    3.1.11_game_guess_number_c
    3.1.12_game_10_second_c
    3.1.13_game_notnot_c