Hello I have this kind of property myProperty :: Conf -> RevertableProperty NoInfo now I have a [Conf] and I want to create also a RevertableProperty NoInfo which apply myProperty for each Conf I tried to find an equivalent of mapM for properties but I found nothing which works as expected. I tried with combineProperties but it failed also with a "cryptic message" mpoints is the [Conf] src/config.hs:250:17: Couldn't match type `CInfo (PropertyListType (Property [NoInfo])) (PropertyListType (Property [NoInfo]))' with `NoInfo' Expected type: RevertableProperty NoInfo Actual type: RevertableProperty (CInfo (PropertyListType (Property [NoInfo])) (PropertyListType (Property [NoInfo]))) In the expression: mount umount In an equation for `mountExp': mountExp b = mount umount where mount = combineProperties "mount nfs files" (mapM mount'' mpoints) umount = combineProperties "umount nfs files" (mapM umount'' mpoints) mpoints = [MountConf "nfs" ("ruche-" ++ beamline ++ ".mydomain.org:/" ++ beamline ++ "-users") ("/nfs/ruche-" ++ beamline ++ "/" ++ beamline ++ "-users"), ....] beamline = show b What is the right way to create a RevertableProperty from a list of RevertableProperty thanks Frederic