code: def set_pwm(self, led_num, value):
          
          self.__check_range('led_number', led_num)
          self.__check_range('led_value', value)
  
          register_low = self.calc_led_register(led_num)
  
          self.write(register_low, value_low(value))
          self.write(register_low + 1, value_high(value))
docs: Set PWM value for the specified LED
  
          :param led_num: LED number (0-15)
          :param value: the 12 bit value (0-4095)