将函数作为参数传递

我知道这里有些非常基本的错误是我看不到的。如果有人对Python有更丰富的经验，可以指出我在这里误解了什么，我将非常感谢。我在下面发布了我的代码的简化版本。要追溯问题的根源，请注意以下几点：

的MainProgram，作为实例化Main = MainProgram()，有一个菜单（self.menu = Startmenu()），它是的一个实例Menu的类。此类Menu具有一个按钮列表（self.buttons = [...]）-在这种情况下只有一个。它们是Button该类的一个实例。现在，我需要将单击按钮时要触发的功能传递给Button该类的实例，这样我才能真正使用它。

我真的要感谢任何经验丰富的用户快速浏览它。我确定我看不到非常基本的东西。我敢打赌，我太累了，看不到它。。。因为家里有一个婴儿，所以只睡了两个小时：D

我的代码：

class MainProgram:
    #Much much more code
    def __init__(self):
        #And so much more code here
         self.menu = StartMenu()

class StartMenu:
    def __init__(self):
        #Much code which is not important to us here
        self.buttons = [Button("d_bt_start", (100, 60)
                                       , testfunc, "TEST-TEXT")]

class Button:
    def __init__(self, image, pos = (0, 0), path = Paths.path_img
                 , alpha = False, func = None, args = None):
        self.img_normal = helper.loadImage(path, image + "_normal.jpg", alpha)
        self.img_hover = helper.loadImage(path, image + "_hover.jpg", alpha)

        self.image = self.img_normal

        self.pos = pos

        self.x = pos[0]
        self.y = pos[1]
        self.width = self.x + self.image.get_width()
        self.height = self.y + self.image.get_height()

        self.mouseover = 0

        self.func = func
        self.args = args

    def update(self, (mx, my)):
        if (mx >= self.x and mx <= self.width and
            my >= self.y and my <= self.height):
            if self.mouseover == 0:
                self.image = self.img_hover
                self.mouseover = 1
        else:
            if self.mouseover == 1:
                self.image = self.img_normal
                self.mouseover = 0

    def clicked(self, button):
        if (mx >= self.x and mx <= self.width and
            my >= self.y and my <= self.height):
            if button == 1:
                self.func(self.args)

应该发生什么：主文件创建StartMenu该类的实例。在StartMenu该类中，我们将一个按钮定义为Button该类的一个实例。testfunc(args)单击该按钮后应触发该功能。到目前为止，该测试功能只是“ TEST-TEXT”参数的打印。

如果我通过功能为

testfunc

然后我得到以下错误回溯：

Traceback (most recent call last):
  File "D:\Python27\_RPG DEMO\DEMO\main.py", line 41, in <module>
   Main = MainProgram()
  File "D:\Python27\_RPG DEMO\DEMO\main.py", line 21, in __init__
    self.menu = menus.StartMenu()
  File "D:\Python27\_RPG DEMO\DEMO\menus.py", line 11, in __init__
    , zztestfile.testfunc, "TESTEST")
  File "D:\Python27\_RPG DEMO\DEMO\buttons.py", line 7, in __init__
    self.img_normal = helper.loadImage(path, image + "_normal.jpg", alpha)
  File "D:\Python27\_RPG DEMO\DEMO\helper.py", line 13, in loadImage
    return pygame.image.load(os.path.join(folder, name)).convert_alpha()
  File "D:\Python27\lib\ntpath.py", line 96, in join
    assert len(path) > 0
TypeError: object of type 'function' has no len()

如果我通过它为：

testfunc("TEST-TEXT")

它触发但导致以下回溯：

TEST-TEXT

Traceback (most recent call last):
  File "D:\Python27\_RPG DEMO\DEMO\main.py", line 41, in <module>
    Main = MainProgram()
  File "D:\Python27\_RPG DEMO\DEMO\main.py", line 21, in __init__
    self.menu = menus.StartMenu()
  File "D:\Python27\_RPG DEMO\DEMO\menus.py", line 11, in __init__
    , testfunc("TEST-TEXT"))
  File "D:\Python27\_RPG DEMO\DEMO\buttons.py", line 7, in __init__
    self.img_normal = helper.loadImage(path, image + "_normal.jpg", alpha)
  File "D:\Python27\_RPG DEMO\DEMO\helper.py", line 15, in loadImage
    return pygame.image.load(os.path.join(folder, name)).convert()
  File "D:\Python27\lib\ntpath.py", line 96, in join
    assert len(path) > 0
TypeError: object of type 'NoneType' has no len()

到目前为止，我已经阅读了一些教程，但是我真的无法弄清楚我对它们的误解。我真的很感谢在此方面的任何帮助！