An example use of a multi-purpose context manager class (with some tricks from withhacks)

panel.py

import imgui
from sys import _getframe, settrace

class Panel:
    """
    This is... not a particularly *useful* example, but it allows us to have one Panel class which can be used for drawing *without* inheritance. See below for examples
    """

    class Closed(Exception):
        ...

    def __init__(self, title, closable=False, is_open=True, default_size=(520, 600)):
        self.title = title
        self.closable = closable
        self.is_open = is_open
        self.default_size = default_size

    def __enter__(self):
        imgui.set_window_size(*self.default_size, imgui.FIRST_USE_EVER)
        if self.is_open:
            _, self.is_open = imgui.begin(self.title, self.closable)
            return self
        else:
            settrace(lambda *args, **kwargs: None)
            frame = _getframe(1)
            frame.f_trace = self.trace

    def trace(self, frame, event, arg):
        raise self.Closed()

    def __exit__(self, exc_type, exc_val, exc_tb):
        if exc_type == self.Closed:
            return True
        imgui.end()
        return False

    def __draw__(self):
        with self:
            self.draw()

    def draw(self):
        ...
    
    
# Panel must be drawn by instantiating it and calling panel.draw()
class ExamplePanel(Panel):
    def draw(self):
        imgui.text("Panel with inheritance!")
        

# Can be inserted directly into your draw method
def draw_a_panel():
    with Panel("Hello Panel!"):
        imgui.text("Panel just made up on the spot!")