TypeError in matplotlib demo

[igurin-invn]

This issue applies to this page: https://www.pythonguis.com/tutorials/pyside6-plotting-matplotlib/

I used this example earlier this year to make a successful GUI (thanks!). I started working on a new GUI, and got a really persistent error:

TypeError: 'PySide6.QtWidgets.QBoxLayout.addWidget' called with wrong argument types:
  PySide6.QtWidgets.QBoxLayout.addWidget(MplCanvas)
Supported signatures:
  PySide6.QtWidgets.QBoxLayout.addWidget(PySide6.QtWidgets.QWidget, int = 0, PySide6.QtCore.Qt.AlignmentFlag = Default(Qt.Alignment))

I eventually found that the matplotlib docs (here) recommend something different:

from matplotlib.backends.backend_qtagg import FigureCanvas

class MplCanvas(FigureCanvas):
    ...

When I changed the data type accordingly, the error went away.