Retrieve ``widgetObj`` specific data previously saved with
        ``qteSaveMacroData``.

        If no data has been stored previously then **None** is
        returned.

        If ``widgetObj`` is **None** then the calling widget
        ``self.qteWidget`` will be used.

        |Args|

        * ``widgetObj`` (**QWidget**): the widget/applet with which
          the data should be associated.

        |Returns|

        * **object**: the previously stored data.

        |Raises|

        * **QtmacsArgumentError** if at least one argument has an invalid type.
        * **QtmacsOtherError** if ``widgetObj`` was not added with
          ``qteAddWidget`` method.

def qteMacroData(self, widgetObj: QtGui.QWidget=None):
        """
        Retrieve ``widgetObj`` specific data previously saved with
        ``qteSaveMacroData``.

        If no data has been stored previously then **None** is
        returned.

        If ``widgetObj`` is **None** then the calling widget
        ``self.qteWidget`` will be used.

        |Args|

        * ``widgetObj`` (**QWidget**): the widget/applet with which
          the data should be associated.

        |Returns|

        * **object**: the previously stored data.

        |Raises|

        * **QtmacsArgumentError** if at least one argument has an invalid type.
        * **QtmacsOtherError** if ``widgetObj`` was not added with
          ``qteAddWidget`` method.

        """

        # Check type of input arguments.
        if not hasattr(widgetObj, '_qteAdmin') and (widgetObj is not None):
            msg = '<widgetObj> was probably not added with <qteAddWidget>'
            msg += ' method because it lacks the <_qteAdmin> attribute.'
            raise QtmacsOtherError(msg)

        # If no widget was specified then use the calling widget.
        if not widgetObj:
            widgetObj = self.qteWidget

        # Retrieve the data structure.
        try:
            _ = widgetObj._qteAdmin.macroData[self.qteMacroName()]
        except KeyError:
            # If the entry does not exist then this is a bug; create
            # an empty entry for next time.
            widgetObj._qteAdmin.macroData[self.qteMacroName()] = None

        # Return the data.
        return widgetObj._qteAdmin.macroData[self.qteMacroName()]