docs: def isAppStore(s):
      """
      Return whether the given store is an application store or not.
      @param s: A Store.
      """
      if s.parent is None:
          return False
      substore = s.parent.getItemByID(s.idInParent)
      return s.parent.query(InstalledOffering,
                            InstalledOffering.application == substore
                            ).count() > 0