SDK • Pico C SDK: adc_gpio_init() do not disable output, just input, why?

Code:

/// \tag::gpio_set_function[]// Select function for this GPIO, and ensure input/output are enabled at the pad.// This also clears the input/output/irq override bits.void gpio_set_function(uint gpio, gpio_function_t fn) {    check_gpio_param(gpio);    invalid_params_if(HARDWARE_GPIO, ((uint32_t)fn << IO_BANK0_GPIO0_CTRL_FUNCSEL_LSB) & ~IO_BANK0_GPIO0_CTRL_FUNCSEL_BITS);    // Set input enable on, output disable off    hw_write_masked(&pads_bank0_hw->io[gpio],                   PADS_BANK0_GPIO0_IE_BITS,                   PADS_BANK0_GPIO0_IE_BITS | PADS_BANK0_GPIO0_OD_BITS    );    // Zero all fields apart from fsel; we want this IO to do what the peripheral tells it.    // This doesn't affect e.g. pullup/pulldown, as these are in pad controls.    io_bank0_hw->io[gpio].ctrl = fn << IO_BANK0_GPIO0_CTRL_FUNCSEL_LSB;#if !PICO_RP2040    // Remove pad isolation now that the correct peripheral is in control of the pad    hw_clear_bits(&pads_bank0_hw->io[gpio], PADS_BANK0_GPIO0_ISO_BITS);#endif/*! \brief  Initialise the gpio for use as an ADC pin *  \ingroup hardware_adc * * Prepare a GPIO for use with ADC by disabling all digital functions. * * \param gpio The GPIO number to use. Allowable GPIO numbers are 26 to 29 inclusive on RP2040 or RP2350A, 40-48 inclusive on RP2350B */static inline void adc_gpio_init(uint gpio) {    invalid_params_if(HARDWARE_ADC, gpio < ADC_BASE_PIN || gpio >= ADC_BASE_PIN + NUM_ADC_CHANNELS - 1);    // Select NULL function to make output driver hi-Z    gpio_set_function(gpio, GPIO_FUNC_NULL);    // Also disable digital pulls and digital receiver    gpio_disable_pulls(gpio);    gpio_set_input_enabled(gpio, false);}