ctools

Currently, we have different ctools to perform different steps of the analysis. Some of them however, only work in case we pass an observation container of unbinned cta observations. Saying it the other way round: many tools fail if the observations contain at least one binned GCTAObservation:

• ctselect
• ctbin
• ctexpcube
• ctpsfcube
• ctbkgcube
• csspec

And probably some others, too. The thrown errors are mostly because RoI information cannot be found. To make the exceptions more meaningful, we might want to add an option to ctool::get_observations, like require_unbinned which throws a meaningful error like “This tool requires an unbinned observation container”.