如何在GtkSourceBuffer中执行正则表达式搜索

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk, GtkSource

def search_textview(textview, pattern):
    buffer = textview.get_buffer()
    start_iter = buffer.get_start_iter()

    # 执行正向搜索
    found, end_iter = buffer.search_forward(pattern, start_iter, flags=0)
    if found:
        # 在找到的位置插入标记
        buffer.place_cursor(end_iter)
        textview.scroll_to_iter(end_iter, 0.0, use_align=True, xalign=0.0, yalign=0.0)
        return

    # 执行反向搜索
    found, end_iter = buffer.search_backward(pattern, start_iter, flags=0)
    if found:
        # 在找到的位置插入标记
        buffer.place_cursor(end_iter)
        textview.scroll_to_iter(end_iter, 0.0, use_align=True, xalign=0.0, yalign=0.0)

# 创建GtkTextView和GtkSourceBuffer
textview = Gtk.TextView()
buffer = textview.get_buffer()

# 设置文本内容
buffer.set_text("This is a sample text for searching.")

# 创建正则表达式模式
pattern = "sample"

# 执行搜索
search_textview(textview, pattern)