code: function pushDeviceFilterByUsers() {
      var users = [];
      for (var _i = 0; _i < arguments.length; _i++) {
          users[_i - 0] = arguments[_i];
      }
      if (users.length <= 0) {
          return {
              type: 'null',
              fieldName: 'user',
              isNull: true
          };
      }
      else if (users.length === 1) {
          return {
              type: 'string',
              fieldName: 'user',
              value: domain.uuidOf(users[0])
          };
      }
      else {
          var uuids = users.map(function (user) { return domain.uuidOf(user); });
          return {
              type: 'stringEnum',
              fieldName: 'user',
              values: uuids
          };
      }
  }
docs: creates a device filter for the user attribute of push devices matching any of a given set of
  users.
  
  @param users* to filter on.
  @returns device filter matching devices of given users.