using more than one linestyle in the same trend line with matplotlib

I want to plot a line using the bold linestyle='k-' and after a certain value on the axes, I want the same line as dashed ('k--') or vice-versa. I want to show the dashed part as an extension to the bold line. One way to do this is to treat them as two individual plots and use different linestyles. I have attached the figure of an example. Just wondering if there was any other way to do this!