geekcomputers/Python · error · TypeError

The background argument must be an instance of Background.

Error message

The background argument must be an instance of Background.

What it means

Tubes (the pipe obstacles thread) validates that background is a Background instance before storing it; it needs the background to compute geometry and draw tube sprites. Any other type triggers this TypeError immediately in __init__.

Source

Thrown at Flappy Bird - created with tkinter/Tubes.py:30

    Classe para criar tubos
    """

    __distance = 0
    __move = 10
    __pastTubes = []

    def __init__(
        self,
        background,
        bird,
        score_function=None,
        *screen_geometry,
        fp=("tube.png", "tube_mourth"),
        animation_speed=50,
    ):
        # Verifica os parâmetros passados e lança um erro caso algo esteja incorreto
        if not isinstance(background, Background):
            raise TypeError(
                "The background argument must be an instance of Background."
            )
        if not len(fp) == 2:
            raise TypeError(
                "The parameter fp should be a sequence containing the path of the images of the tube body and the tube mouth."
            )
        if not isinstance(bird, Bird):
            raise TypeError("The birdargument must be an instance of Bird.")
        if not callable(score_function):
            raise TypeError("The score_function argument must be a callable object.")

        Thread.__init__(self)

        # Instância os parâmetros
        self.__background = background
        self.image_path = fp
        self.__animation_speed = animation_speed
        self.__score_method = score_function

View on GitHub (pinned to 40f4cd2652)

Solutions

1. Instantiate Background first and pass it to Tubes(background=bg, bird=bird, score_function=...)
2. Verify the import path of Background matches the class actually used (no duplicate shadowing module)
3. In tests, mock the Background class in the Tubes module namespace

Example fix

# before
tubes = Tubes(root, bird, score_fn)
# after
bg = Background(root)
tubes = Tubes(bg, bird, score_fn)

from Background import Background
assert isinstance(bg, Background)

def is_background(obj) -> bool:
    return type(obj).__name__ == 'Background'

try:
    tubes = Tubes(bg, bird, score_fn)
except TypeError as e:
    print('Tubes argument validation failed:', e)

When it happens

Trigger: Constructing Tubes with a Tk root, Canvas, or None instead of a Background; instantiating Tubes before the Background in the startup sequence.

Common situations: Start-up ordering bugs in the game's main script; refactoring that bypasses the Background abstraction; test harnesses passing fake objects.

Related errors

• The tk_instance argument must be an instance of Tk.
• The background argument must be an instance of Background.
• The birdargument must be an instance of Bird.
• The parameter fp should be a sequence containing the path of
• The gameover_method argument must be a callable object.

AI-assisted analysis of geekcomputers/Python@40f4cd2652 (2026-08-27). Data as JSON: /api/errors/51698cf4ea9cab8c. Report an issue: GitHub.