def _set_function(self, value):
if value == 'input':
if self.pwm_active:
raise InputDeviceError('PWM Pin cannot be set to input')
self._enable_gpio()
elif value == 'pwm':
if self.gpio_active:
raise PinPWMUnsupported('GPIO Pin cannot be set to pwm')
self._enable_pwm()
elif self._active_pin() is None:
self._enable_gpio()
if value != 'input':
self._poller.stop_polling()
self._active_pin().set_function(value)