[PySide] AttributeError: 'QwtPlotCanvas' object has no attribute 'Sunken'

[PierreRaybaut]

With PySide 6.5.2, Python 3.11.3 on Windows:

Traceback (most recent call last):
  File "C:\Dev\PythonQwt\qwt\plot_canvas.py", line 595, in event
    return QFrame.event(self, event)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Dev\PythonQwt\qwt\plot_canvas.py", line 654, in paintEvent
    self.drawBorder(painter)
  File "C:\Dev\PythonQwt\qwt\plot_canvas.py", line 768, in drawBorder
    if frameShadow == self.Sunken:
                      ^^^^^^^^^^^
AttributeError: 'QwtPlotCanvas' object has no attribute 'Sunken'
QBackingStore::endPaint() called with active painter; did you forget to destroy it or call QPainter::end() on it?
QPaintDevice: Cannot destroy paint device that is being painted
Traceback (most recent call last):
  File "C:\Dev\PythonQwt\qwt\plot_canvas.py", line 595, in event
    return QFrame.event(self, event)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Dev\PythonQwt\qwt\plot_canvas.py", line 654, in paintEvent
    self.drawBorder(painter)
  File "C:\Dev\PythonQwt\qwt\plot_canvas.py", line 768, in drawBorder
    if frameShadow == self.Sunken:
                      ^^^^^^^^^^^
AttributeError: 'QwtPlotCanvas' object has no attribute 'Sunken'
QBackingStore::endPaint() called with active painter; did you forget to destroy it or call QPainter::end() on it?
QPaintDevice: Cannot destroy paint device that is being painted