When using PVDataSet to fetch a PV that doesn't exist, the update() method returns None, which is the same thing it does when it succeeds. When using a list of PVs which exist and which don't, it does the same thing, but there is no data for the PVs which do exist (the .value and .timestamp members are None), and then one has to figure out which specific PV wasn't archived, which is an information that should have been reported in failure information.
When using PVDataSet to fetch a PV that doesn't exist, the
update()method returnsNone, which is the same thing it does when it succeeds. When using a list of PVs which exist and which don't, it does the same thing, but there is no data for the PVs which do exist (the.valueand.timestampmembers areNone), and then one has to figure out which specific PV wasn't archived, which is an information that should have been reported in failure information.