-void IS31FL3731_init( uint8_t addr );
-void IS31FL3731_write_register( uint8_t addr, uint8_t reg, uint8_t data );
-void IS31FL3731_write_pwm_buffer( uint8_t addr, uint8_t *pwm_buffer );
+uint8_t IS31FL3731_init( uint8_t addr );
+uint8_t IS31FL3731_write_register( uint8_t addr, uint8_t reg, uint8_t data );
+uint8_t IS31FL3731_write_pwm_buffer( uint8_t addr, uint8_t *pwm_buffer );