从类的__init__中调用Button委托者

Question

My GUI program uses a number of buttons that have a couple very specific features, so I'm writing a class that wraps these methods around a button so I don't need to keep rewriting simple functions for each button. I have the class:

class ToggleableButton(Button):     
    __isToggled = False
    __root = None
    __bindMap = []

    # how do I correctly structure the init ?
    def __init__(self, master=None, cnf={}, **kw):
        Button.__init__(self, master, cnf, kw)

    def bind(self, root, bindKey, func):
        # doing stuff

    def Toggle(self, toggle=False):
        # doing stuff

and I want to be able to create the object just like I'd create a button:

drawButton = ToggleableButton(frame, image=img, width=30, command=func)
drawButton = ToggleableButton(frame, image=anotherimg)

how can I declare the class __init__ method to mimic that of the button? Currently if I write test = ToggleableButton(frame, text="hi", width=10, command=func) I'll get the error:

tools.py, line 59, in __init__
    Button.__init__(self, master, cnf, kw)
TypeError: __init__() takes at most 3 arguments (4 given)

Answer 1

You need to apply (splat) the extra keyword arguments:

Button.__init__(self, master, cnf, **kw)
                                   ^^

Otherwise, you will be passing the whole kw dict as a single positional argument. This raises an error since Button.__init__ only accepts three positional arguments ( self , master , and cnf ), not four.