QChat painting line, QSplineSeries append method can add data, connect a pile of data, form a line, but I want to draw a line, can disconnect between variables is to use a QSplineSeries draw line, a set of data in a certain period of time without the data, not painting, and follow-up time data, start painting again, if only append to connect all the data before and after, look in the middle period of time there is a data, in fact is not, how do you achieve?