How to decently destroy opengl resources when using QOpenGLWidget in pyqt5

First of all, My codes are as follows:

from PyQt5.QtWidgets import QApplication, QOpenGLWidget, QMainWindow
from PyQt5.QtGui import QPainter, QOpenGLShader, QOpenGLShaderProgram, QMatrix4x4, QOpenGLBuffer, QOpenGLVertexArrayObject
from PyQt5.QtCore import Qt, QTimer

import numpy as np
import OpenGL.GL as gl
import sys

class OpenGLWidget(QOpenGLWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.frame_count = 0

    def initializeGL(self):
        self.program = QOpenGLShaderProgram()
        self.program.addShaderFromSourceCode(QOpenGLShader.Vertex, """
            attribute highp vec4 aPos;
            void main() {
                gl_Position = aPos;
            }
        """)
        self.program.addShaderFromSourceCode(QOpenGLShader.Fragment, """
            void main() {
                gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
            }
        """)

        self.program.link()
        self.program.bind()

        self.vertices = np.array([
            [-0.5, -0.5, 0.0, 1.0],
            [0.0, -0.5, 0.0, 1.0],
            [-0.25, 0.0, 0.0, 1.0],
            [-0.5, 0.5, 0.0, 1.0],
            [0.0, 0.5, 0.0, 1.0],
        ], dtype=np.float32)

        self.indices = np.array([
            0,1,2,2,3,4
        ], dtype=np.uint16)
        
        self.vao = QOpenGLVertexArrayObject()
        self.vbo = QOpenGLBuffer(QOpenGLBuffer.VertexBuffer)
        self.ibo = QOpenGLBuffer(QOpenGLBuffer.IndexBuffer)
        self.vao.create()
        self.vbo.create()
        self.ibo.create()
        self.vao.bind()        
        self.vbo.bind()
        self.ibo.bind()
        self.vbo.allocate(self.vertices.nbytes)
        self.ibo.allocate(self.indices.nbytes)
        self.vbo.write(0, self.vertices.tobytes(), self.vertices.nbytes)        
        self.ibo.write(0, self.indices.tobytes(), self.indices.nbytes)
        posAttribLoc = self.program.attributeLocation("aPos")
        self.program.setAttributeBuffer(posAttribLoc, gl.GL_FLOAT, 0, 4, 0)
        self.program.enableAttributeArray(posAttribLoc) 
        self.vbo.release()
        self.vao.release()
    
    def paintGL(self):
        gl = self.context().versionFunctions() 
        gl.glClearColor(0.33,0.33,0.33, 1.0)
        gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT)
        self.vao.bind()
        self.program.bind()

        gl.glDrawElements(gl.GL_TRIANGLES, len(self.indices), gl.GL_UNSIGNED_SHORT, None)
        self.frame_count += 1
    
    def resizeGL(self, width, height):
        gl.glViewport(0, 0, width, height)
    
    def __del__(self):
        self.vao.destroy()
        self.vbo.destroy()
        self.ibo.destroy()        
        self.program.removeAllShaders()
        pass

if __name__ == '__main__':
    app = QApplication(sys.argv)
    widget = OpenGLWidget()
    window = QMainWindow()    
    window.setCentralWidget(widget)
    window.setGeometry(0,0,640,480)
    window.show()
    sys.exit(app.exec_())

Everything goes well, I can render it as expected. But python complains:

in __del__
RuntimeError: wrapped C/C++ object of type QOpenGLVertexArrayObject has been deleted

when I close the window. Guess the buffer is freed twice so I change the destructor to

    def __del__(self):
        pass

while the interpreter complain

QOpenGLVertexArrayObject::destroy() failed to restore current context

After closing. I think there must be something wrong on freeing, can anyone figure out proper way to release these buffers?

UPDAETE
Enlightened by Resource Initialization and Cleanup topic within Qt doc, we can connect aboutToBeDestroyed signal to a customized slot function for cleanup:

    def __init__(self, parent=None):
        super().__init__(parent)
        self.frame_count = 0
        self.glContext = None

    def paintGL(self):
        if self.glContext is None: 
            self.glContext = self.context()
            self.glContext.aboutToBeDestroyed.connect(self.cleanup)

        gl = self.glContext.versionFunctions() 
        gl.glClearColor(0.33,0.33,0.33, 1.0)
        gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT)
        self.vao.bind()
        self.program.bind()

        gl.glDrawElements(gl.GL_TRIANGLES, len(self.indices), gl.GL_UNSIGNED_SHORT, None)
        self.frame_count += 1

    def cleanup(self):
        print('cleanup called')
        self.makeCurrent()
        self.vao.destroy()
        self.vbo.destroy()
        self.ibo.destroy()        
        self.program.removeAllShaders()
        self.doneCurrent()

However, cleanup still not called after closing window

source https://stackoverflow.com/questions/76226693/how-to-decently-destroy-opengl-resources-when-using-qopenglwidget-in-pyqt5