code: function unique(acls) {
      var newAcls = [];
      // Remove empty and duplicate ACLs from specified list
      acls.forEach(function(acl) {
        if (!acl.isEmpty()) {
          var found = false;
          var len = newAcls.length;
          for (var i = 0; !found && i < len; i++)
            found = newAcls[i].equals(acl);
          if (!found)
            newAcls.push(acl);
        }
      });
      return newAcls;
    }
docs: An ACL either contains a single access mask or a list of nested ACLs (but not both)