entity Photo in [Account, Album];
entity Video in [Account, Album];
entity Account;
entity Album in [Account];
entity UserGroup;
entity User in [UserGroup];
entity Administrator;

action view, delete, edit
  appliesTo { principal: [User], resource: [Photo, Video, Album] };
action listPhotos
  appliesTo { principal: [User], resource: [Album, Photo, Video] };