The SRCLIST table has no entry with the specified source
Either the input event dataset contains no exposure map extensions
at all, or none of the exposure maps enclose a non-zero area,
which indicates that no frames passed through the filter.
It is permissible, but pointless, to set parameters
withspectrum and withbkgset both to false.
corrective action: The task does nothing and completes without error.
The channel definitions in the EVENTS table must align
with the channel definitions in the exposure map extensions. In
the case of a null exposure map (see rgsfilter) this merely
indicates that for this chip no frames passed through the filter,
which may be cause for concern.
corrective action: The exposure map is discarded and the spectrum may not be correct.