def PrintBox(loc, height, width, style='r-'):
    """A utility function to help visualizing boxes."""
    xmin, ymin, xmax, ymax = loc[0] * width, loc[1] * height, loc[2] * width, loc[3] * height 
    #pyplot.plot([xmin, xmax, xmax, xmin, xmin], [ymin, ymin, ymax, ymax, ymin], style)
    return [xmin, ymin, xmax, ymax]