class_docstr: Qt widget containing a vispy Canvas.
  
  This is a convenience class that allows a vispy canvas to be embedded
  directly into a Qt application.
  All methods and properties of the Canvas are wrapped by this class.
  
  Parameters
  ----------
  parent : QWidget or None
      The Qt parent to assign to this widget.
  canvas : instance or subclass of Canvas
      The vispy Canvas to display inside this widget, or a Canvas subclass
      to instantiate using any remaining keyword arguments.
docstr: Call update() on both this widget and the internal canvas.
code: def update(self):
      """Call update() on both this widget and the internal canvas."""
      QWidget.update(self)
      self._canvas.update()
  
file_path: vispy/vispy/app/qt.py
imports: from .backends import qt_lib
label_desc: Use image node_id 3 for calling the QtCanvas obj's underlying member method code with example usage: obj.update() without return types