docs: def qteMakeWidgetActive(self, widgetObj: QtGui.QWidget):
          """
          Give keyboard focus to ``widgetObj``.
  
          If ``widgetObj`` is **None** then the internal focus state
          is reset, but the focus manger will automatically
          activate the first available widget again.
  
          |Args|
  
          * ``widgetObj`` (**QWidget**): the widget to focus on.
  
          |Returns|
  
          * **None**
  
          |Raises|
  
          * **QtmacsOtherError** if ``widgetObj`` was not added with
              ``qteAddWidget``.
          """
          # Void the active widget information.
          if widgetObj is None:
              self._qteActiveWidget = None
              return
  
          # Ensure that this applet is an ancestor of ``widgetObj``
          # inside the Qt hierarchy.
          if qteGetAppletFromWidget(widgetObj) is not self:
              msg = 'The specified widget is not inside the current applet.'
              raise QtmacsOtherError(msg)
  
          # If widgetObj is not registered with Qtmacs then simply declare
          # it active and return.
          if not hasattr(widgetObj, '_qteAdmin'):
              self._qteActiveWidget = widgetObj
              return
  
          # Do nothing if widgetObj refers to an applet.
          if widgetObj._qteAdmin.isQtmacsApplet:
              self._qteActiveWidget = None
              return
  
          # Housekeeping: remove non-existing widgets from the admin structure.
          self.qteAutoremoveDeletedWidgets()
  
          # Verify the widget is registered for this applet.
          if widgetObj not in self._qteAdmin.widgetList:
              msg = 'Widget is not registered for this applet.'
              self.qteLogger.error(msg, stack_info=True)
              self._qteActiveWidget = None
              return
  
          # The focus manager in QtmacsMain will hand the focus to
          # whatever the _qteActiveWidget variable of the active applet
          # points to.
          self.qteSetWidgetFocusOrder((self._qteActiveWidget, widgetObj))
          self._qteActiveWidget = widgetObj