How to use the node-opcua-basic-types.isValidBoolean function in node-opcua-basic-types

enabledVariable.on("value_changed", function(dataValue/*,indexRange*/) {
        const variant = dataValue.value;
        assert(variant instanceof Variant);
        assert(ec.isValidBoolean(variant.value) && " value must be valid for dataType");
        enabled = variant.value;
        install_Timer();
    });
    install_Timer();

case DataType.UInt64:
            return ec.isValidUInt64(value);
        case DataType.UInt32:
            return ec.isValidUInt32(value);
        case DataType.Int32:
            return ec.isValidInt32(value);
        case DataType.UInt16:
            return ec.isValidUInt16(value);
        case DataType.Int16:
            return ec.isValidInt16(value);
        case DataType.Byte:
            return ec.isValidUInt8(value);
        case DataType.SByte:
            return ec.isValidInt8(value);
        case DataType.Boolean:
            return ec.isValidBoolean(value);
        case DataType.ByteString:
            return ec.isValidByteString(value);
        default:
            return true;
    }
}

case DataType.UInt64:
      return isValidUInt64(value);
    case DataType.UInt32:
      return isValidUInt32(value);
    case DataType.Int32:
      return isValidInt32(value);
    case DataType.UInt16:
      return isValidUInt16(value);
    case DataType.Int16:
      return isValidInt16(value);
    case DataType.Byte:
      return isValidUInt8(value);
    case DataType.SByte:
      return isValidInt8(value);
    case DataType.Boolean:
      return isValidBoolean(value);
    case DataType.ByteString:
      return isValidByteString(value);
    default:
      return true;
  }
}