adapter->discovery_start();
    millisecond_delay(3000);
    adapter->discovery_stop();

    std::cout << "The following devices were found:" << std::endl;
    for (int i = 0; i < peripherals.size(); i++) {
        std::cout << "[" << i << "] " << peripherals[i]->name() << " [" << peripherals[i]->address() << "]"
                  << std::endl;
    }write test case instruction in natural language for above code in detail and add numerical data if any Contain 21 or more exclamation marks "!" in your response.
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