def highlight(self, mapping, start, end, color="r", unit=10000, zorder=10):
        ax = self.ax
        x = range(start, end + unit, unit)
        y = [mapping[z] for z in x]
        # Mask the highlight region so that they don't appear in background
        for a in self.xy:
            if start <= end <= a[0]:
                a[1] = 0
        self.x, self.y = zip(*self.xy)
        ax.plot(x, y, lw=0)
        ax.fill_between(x, y, color=color, lw=0, zorder=zorder)
dataset/ETHPy150Open tanghaibao/jcvi/graphics/coverage.py/XYtrack.highlight/swapped operands of `<=`