def METHOD_NAME():
    """Start the document watcher."""
    global watcher
    if watcher is None:
        watcher = QFileSystemWatcher()
        app.documentLoaded.connect(documentLoaded)
        app.documentUrlChanged.connect(documentUrlChanged)
        app.documentClosed.connect(documentClosed)
        app.documentSaving.connect(whileSaving)
        watcher.fileChanged.connect(fileChanged)
        for d in app.documents:
            documentLoaded(d)