kivy-如何在按下MDFloatingActionButtonSpeedDial后添加功能

from kivy.uix.button import Button
from kivy.uix.floatlayout import FloatLayout
from kivymd.uix.button import MDFloatingActionButtonSpeedDial

class MyLayout(FloatLayout):
    pass

class MyLayout(FloatLayout):
    def __init__(self, **kwargs):
        super(MyLayout, self).__init__(**kwargs)
        
        fab = MDFloatingActionButtonSpeedDial()
        fab.data = {
            'plus': '添加',
            'edit': '编辑',
            'delete': '删除'
        }
        self.add_widget(fab)

class MyLayout(FloatLayout):
    def __init__(self, **kwargs):
        super(MyLayout, self).__init__(**kwargs)
        
        fab = MDFloatingActionButtonSpeedDial()
        fab.data = {
            'plus': '添加',
            'edit': '编辑',
            'delete': '删除'
        }
        fab.on_action_button_click = self.on_action_button_click
        self.add_widget(fab)
    
    def on_action_button_click(self, button):
        if button.icon == 'plus':
            # 执行添加功能的代码
            pass
        elif button.icon == 'edit':
            # 执行编辑功能的代码
            pass
        elif button.icon == 'delete':
            # 执行删除功能的代码
            pass