This page is for the Sherpa 4.11 release. Please see the
Sherpa home page for the latest release.
A background data set must be assigned an ID
('bkg_id') before being used with get_bkg_model.
If a background data set is not automatically loaded with
the corresponding source data set and assigned a Sherpa
'bkg_id' of "1", "2", etc., then the background data set
must be assigned an ID with set_bkg
before it can be used with