如何从wx python CtrlText中检索文本？

import wx

class MyFrame(wx.Frame):
    def __init__(self):
        wx.Frame.__init__(self, None, title="CtrlText检索示例")
        panel = wx.Panel(self)

        # 创建CtrlText控件
        self.ctrl_text = wx.TextCtrl(panel, style=wx.TE_MULTILINE)

        # 创建按钮
        search_button = wx.Button(panel, label="检索")
        search_button.Bind(wx.EVT_BUTTON, self.on_search)

        # 创建布局
        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(self.ctrl_text, proportion=1, flag=wx.EXPAND)
        sizer.Add(search_button, flag=wx.ALIGN_CENTER)

        panel.SetSizer(sizer)
        self.Show()

    def on_search(self, event):
        # 获取CtrlText中的文本内容
        text = self.ctrl_text.GetValue()

        # 在文本内容中检索特定字符串
        if "关键词" in text:
            wx.MessageBox("找到了关键词！", "提示", wx.OK | wx.ICON_INFORMATION)
        else:
            wx.MessageBox("未找到关键词！", "提示", wx.OK | wx.ICON_INFORMATION)

app = wx.App()
frame = MyFrame()
app.MainLoop()