checkConfiguredPackage :: (Package srcpkg, Package ipkg)
                       => GenericPlanPackage ipkg srcpkg iresult ifailure
                       -> Maybe srcpkg
checkConfiguredPackage (Configured pkg) = Just pkg
checkConfiguredPackage :: (Package srcpkg, Package ipkg)
                       => GenericPlanPackage ipkg srcpkg iresult ifailure
                       -> Maybe srcpkg
checkConfiguredPackage (Configured pkg) = Just pkg
checkConfiguredPackage (Configured pkg) = Just pkg