def METHOD_NAME(self, msg=None):
    ''' Shows shadowed foreground with message
    :param msg: Message that will be displayed
    (set to `Please wait...` if `None` entered)
    :type msg: str
    '''
    if msg is None:
        msg = 'Please wait...'
    self.shadow_widget.message = msg
    self.shadow_widget.setVisible(True)
    self.resizeEvent()
    QtWidgets.QApplication.processEvents()