You want to create a Button class that supports both on_press and on_release callbacks. Which code correctly implements this so pressing and releasing the button calls the right functions?

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Raspberry Pi - gpiozero Library

You want to create a Button class that supports both on_press and on_release callbacks. Which code correctly implements this so pressing and releasing the button calls the right functions?

class Button:
    def __init__(self):
        # What should go here?
    def press(self):
        # What should go here?
    def release(self):
        # What should go here?

button = Button()
button.on_press = lambda: print('Pressed')
button.on_release = lambda: print('Released')

button.press()
button.release()

AInitialize on_press and on_release as True; check if True before calling

BInitialize on_press and on_release to empty strings; print them in press and release

CDo not initialize callbacks; call them directly in press and release methods

DInitialize on_press and on_release to None; call them if set in press and release methods

Step-by-Step Solution

Solution:

Step 1: Initialize callbacks properly
Set self.on_press and self.on_release to None in __init__ to indicate no function assigned yet.
Step 2: Call callbacks safely in methods
In press and release, check if the callback is not None before calling it to avoid errors.
Final Answer:
Initialize on_press and on_release to None; call them if set in press and release methods -> Option D
Quick Check:
Initialize None and check before call = D [OK]

Quick Trick: Set callbacks to None and check before calling [OK]

Common Mistakes:

Using wrong default values like empty strings or True
Calling callbacks without checking if assigned
Not supporting both press and release callbacks

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You want to create a Button class that supports both on_press and on_release callbacks. Which code correctly implements this so pressing and releasing the button calls the right functions?

Step 1: Initialize callbacks properly

Step 2: Call callbacks safely in methods

Final Answer:

Quick Check:

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