How to use the classes.query.File.get function in classes

def add_file(self, filepath):
        path, filename = os.path.split(filepath)

        # Add file into project
        app = get_app()
        _ = get_app()._tr

        # Check for this path in our existing project data
        file = File.get(path=filepath)

        # If this file is already found, exit
        if file:
            return

        # Load filepath in libopenshot clip object (which will try multiple readers to open it)
        clip = openshot.Clip(filepath)

        # Get the JSON for the clip's internal reader
        try:
            reader = clip.Reader()
            file_data = json.loads(reader.Json())

            # Determine media type
            if file_data["has_video"] and not is_image(file_data):
                file_data["media_type"] = "video"

def addClip(self, data, position):

        # Get app object
        app = get_app()

        # Search for matching file in project data (if any)
        file_id = data[0]
        file = File.get(id=file_id)

        if not file:
            # File not found, do nothing
            return

        if (file.data["media_type"] == "video" or file.data["media_type"] == "image"):
            # Determine thumb path
            thumb_path = os.path.join(info.THUMBNAIL_PATH, "%s.png" % file.data["id"])
        else:
            # Audio file
            thumb_path = os.path.join(info.PATH, "images", "AudioThumbnail.png")

        # Get file name
        path, filename = os.path.split(file.data["path"])

        # Convert path to the correct relative path (based on this folder)

def add_file(self, filepath):
        path, filename = os.path.split(filepath)

        # Add file into project
        app = get_app()
        _ = get_app()._tr

        # Check for this path in our existing project data
        file = File.get(path=filepath)

        # If this file is already found, exit
        if file:
            return

        # Load filepath in libopenshot clip object (which will try multiple readers to open it)
        clip = openshot.Clip(filepath)

        # Get the JSON for the clip's internal reader
        try:
            reader = clip.Reader()
            file_data = json.loads(reader.Json())

            # Set media type
            file_data["media_type"] = "image"

# Get clip path
                    xml_file_id = clip_element.getElementsByTagName("file")[0].getAttribute("id")
                    clip_path = ""
                    if clip_element.getElementsByTagName("pathurl"):
                        clip_path = clip_element.getElementsByTagName("pathurl")[0].childNodes[0].nodeValue
                    else:
                        # Skip clipitem if no clippath node found
                        # This usually happens for linked audio clips (which OpenShot combines audio and thus ignores this)
                        continue

                    clip_path, is_modified, is_skipped = find_missing_file(clip_path)
                    if is_skipped:
                        continue

                    # Check for this path in our existing project data
                    file = File.get(path=clip_path)

                    # Load filepath in libopenshot clip object (which will try multiple readers to open it)
                    clip_obj = openshot.Clip(clip_path)

                    if not file:
                        # Get the JSON for the clip's internal reader
                        try:
                            reader = clip_obj.Reader()
                            file_data = json.loads(reader.Json())

                            # Determine media type
                            if file_data["has_video"] and not is_image(file_data):
                                file_data["media_type"] = "video"
                            elif file_data["has_video"] and is_image(file_data):
                                file_data["media_type"] = "image"
                            elif file_data["has_audio"] and not file_data["has_video"]:

# Path is expected to have 3 matched components (third is optional though)
            #   /thumbnails/FILE-ID/FRAME-NUMBER/   or
            #   /thumbnails/FILE-ID/FRAME-NUMBER/path/
            self.send_response_only(200)
        else:
            self.send_error(404)
            return

        # Get URL parts
        file_id = url_output.group('file_id')
        file_frame = int(url_output.group('file_frame'))
        only_path = url_output.group('only_path')

        try:
            # Look up file data
            file = File.get(id=file_id)

            # Ensure file location is an absolute path
            file_path = file.absolute_path()
        except AttributeError:
            # Couldn't match file ID
            self.send_error(404)
            return

        # Send headers
        if not only_path:
            self.send_header('Content-type', 'image/png')
        else:
            self.send_header('Content-type', 'text/html')
        self.end_headers()

        # Locate thumbnail

def actionAdd_to_Timeline_trigger(self, event):
        # Loop through selected files
        f = None
        files = []
        for file_id in self.selected_files:
            # Find matching file
            files.append(File.get(id=file_id))

        # Get current position of playhead
        fps = get_app().project.get(["fps"])
        fps_float = float(fps["num"]) / float(fps["den"])
        pos = (self.preview_thread.player.Position() - 1) / fps_float

        # show window
        from windows.add_to_timeline import AddToTimeline
        win = AddToTimeline(files, pos)
        # Run the dialog event loop - blocking interaction on this window during this time
        result = win.exec_()
        if result == QDialog.Accepted:
            log.info('confirmed')
        else:
            log.info('canceled')

def actionDuplicateTitle_trigger(self, event):

        # Get selected svg title file
        selected_file_id = self.selected_files[0]
        file = File.get(id=selected_file_id)
        file_path = file.data.get("path")

        # show dialog for editing title
        from windows.title_editor import TitleEditor
        win = TitleEditor(file_path, duplicate=True)
        # Run the dialog event loop - blocking interaction on this window during that time
        result = win.exec_()

def actionDuplicateTitle_trigger(self, event):

        # Get selected svg title file
        selected_file_id = self.selected_files[0]
        file = File.get(id=selected_file_id)
        file_path = file.data.get("path")

        # show dialog for editing title
        from windows.title_editor import TitleEditor
        win = TitleEditor(file_path, duplicate=True)
        # Run the dialog event loop - blocking interaction on this window during that time
        result = win.exec_()