PySide2 : QOpenGLFunction

class TestRender(QObject,QOpenGLFunctions):
    def __init__( self ):
        super().__init__()
        self.profile = QOpenGLVersionProfile()
        self.gl = None
        self.viewportSize = QSize()
        self.t = 0.0
        self.program = None
        self.window = None
        self.initialize()

    def setT( self, t ):
        self.t = t

    ....

    def initialize( self ):
        if self.program == None:
            initializeOpenGLFunctions()   #ERROR: The application hangs. 
        

    def paint( self ):
        if self.program == None:
            self.initialize()

        ... 
        glDisable(GL_DEPTH_TEST)       #ERROR: The application hangs.