What does this Data Model error mean?

# DMCOPY (CIAO): DM Parse error: cannot mix EXCLUDE and FILTER

The Data Model cannot combine an exclude filter with any other kind of filter. In this example, the combination of exclude and the energy range filter produces the error:

unix% dmcopy file.fits"[exclude sky=region(mask.fits)][energy=300:5000][bin det=8]" out.fits

Failed to open virtual file file.fits[exclude sky=region(mask.fits)][energy=300:5000][bin det=8]
# DMCOPY (CIAO): DM Parse error: cannot mix EXCLUDE and FILTER

The filtering can be split into two separate dmcopy commands to apply the mask and the energy filter to the file:

unix% dmcopy file.fits"[exclude sky=region(mask.fits)]" file_masked.fits
unix% dmcopy file_masked.fits"[energy=300:5000][bin det=8]" out.fits