'**SUMMARY**
This method renders all of the holes (if any) that are present in the blob.
**PARAMETERS**
* *color* - The color to render the blob\'s holes.
* *alpha* - The alpha value of the rendered blob hole.
* *width* - The width of the drawn blob hole in pixels, if w=-1 then the polygon is filled.
* *layer* - If layer is not None, the blob is rendered to the layer versus the source image.
**RETURNS**
This method either works on the original source image, or on the drawing layer provided.
The method does not modify object itself.
**EXAMPLE**
>>> img = Image("lenna")
>>> blobs = img.findBlobs(128)
>>> blobs[-1].drawHoles(color=Color.GREEN,width=3,alpha=128)
>>> img.show()'

def drawHoles(self, color=Color.GREEN, alpha=(-1), width=(-1), layer=None):

    if (self.mHoleContour is None):
        return
    if (layer is None):
        layer = self.image.dl()
    if (width < 0):
        for h in self.mHoleContour:
            layer.polygon(h, color, filled=True, alpha=alpha)
    else:
        for h in self.mHoleContour:
            lastp = h[0]
            for nextp in h[1::None]:
                layer.line((int(lastp[0]), int(lastp[1])), (int(nextp[0]), int(nextp[1])), color, width=width, alpha=alpha, antialias=False)
                lastp = nextp
            layer.line(h[0], h[(-1)], color, width=width, alpha=alpha, antialias=False)
