How can I set the UIColor of a UIBezierPath in Swift? : <p>Let's say I have something like this in Objective-C</p>

<pre><code> - (void)drawRect:(CGRect)rect {
  if (1 &lt; [_points count]) {
    UIBezierPath *path = [UIBezierPath bezierPath];
    [path setLineWidth:3.];
    MyPoint *point = _points[0];
    [path moveToPoint:point.where];
    NSTimeInterval now = [NSDate timeIntervalSinceReferenceDate];

    for (int i = 1; i &lt; (int)_points.count; ++i) {
      point = _points[i];
      [path addLineToPoint:point.where];
      float alpha = 1;
      if (1 &lt; now - point.when) {
        alpha = 1 - MIN(1, now - (1+point.when));
      }
      [[UIColor colorWithWhite:0 alpha:alpha] set]; //THIS LINE
      [path stroke];
      path = [UIBezierPath bezierPath];
      [path setLineWidth:3.];
      [path moveToPoint:point.where];
    }
  }
}
</code></pre>

<p>How would I do the following line <code>[[UIColor colorWithWhite:0 alpha:alpha] set];</code> in Swift?</p>
