Add a Notify block to your trigger model, described on page 8-32 of the 2450 Reference Manual: https://www.tek.com/en/keithley-source-measure-units/keithley-smu-2400-series-sourcemeter-manual/model-2450-interactive-sou
The smu.source.sweeplinear() function simply creates a trigger model that you're free to edit after it's created. If you're doing this programmatically (it sounds like it) you will need to edit the block numbers of all the blocks that come after wherever you insert the Notify block. I would recommend trying this from the front panel first so you can use the display to get a better idea of the trigger flow, you can also use trigger.model.getblocklist() to see the whole trigger model via a remote interface.
