How to use the vscode-languageclient.DidChangeConfigurationNotification.type function in vscode-languageclient

configurationListener = workspace.onDidChangeConfiguration(() => {
			client.sendNotification(DidChangeConfigurationNotification.type, { settings: null });
		});
	}

this.disposables.push(workspace.onDidChangeConfiguration(() => {
			this.folderSettings.clear();
			this.globalSettings = null;
			this.client.sendNotification(DidChangeConfigurationNotification.type, { settings: null });
		}));
	}

configurationListener = Workspace.onDidChangeConfiguration(() => {
            lspcodelens.configurationChanged();
            client.sendNotification(DidChangeConfigurationNotification.type, { settings: null });
        });
        fileSystemWatcher = workspace.createFileSystemWatcher('**/*.erl');

this.configurationListener = workspace.onDidChangeConfiguration(() => {
      client.sendNotification(DidChangeConfigurationNotification.type, {
        settings: null
      });
    });
  }

configurationListener = workspace.onDidChangeConfiguration(() => {
			client.sendNotification(DidChangeConfigurationNotification.type, { settings: null });
		});

didChangeConfiguration: () => {
            languageClient.sendNotification(DidChangeConfigurationNotification.type, { settings: getXMLSettings(requirements.java_home) });
            onConfigurationChange();
          }
        }