from ofColor.h:
```cpp
void setHsb(float hue, float saturation, float brightness, float alpha = limit() );
```

does this mean the a is not needed in both setHue() and setHueAngle()?

Is that line equivalent to:

```cpp
void setHsb(float hue, float saturation, float brightness, float alpha){
// some implementation
_alpha = alpha
}
void setHsb(float hue, float saturation, float brightness) {
// some implementation
_alpha = limit();
}
```