Как вывести всплывающую подсказку PyQt5 QSystemTrayIcon?

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel, QGridLayout,\
 QWidget, QCheckBox, QSystemTrayIcon, QSpacerItem, QSizePolicy, QMenu, QAction,\
 QStyle, qApp, QMessageBox, QComboBox
from PyQt5.QtCore import QSize, QCoreApplication 
from PyQt5.QtGui import QIcon
 
class SystemTrayIcon(QSystemTrayIcon):
  tray_icon = True
  def __init__(self, icon, parent=None):
        QSystemTrayIcon.__init__(self, icon, parent)
        self.tray_icon = QSystemTrayIcon(self)
        menu = QMenu(parent)
        quit_action = QAction("Exit", self)
        menu.addAction(quit_action)
        quit_action.triggered.connect(qApp.quit)
        tray_menu = QMenu()
        self.iconLabel = QLabel("TEST")
        tray_menu.addAction(quit_action)
        self.setContextMenu(tray_menu)
        self.show()
 
def main():
    app = QApplication(sys.argv)
    w = QWidget()
    trayIcon = SystemTrayIcon(QIcon("~/pictures/icons/exit.png"), w)
    trayIcon.show()
    sys.exit(app.exec_())
 
if __name__ == '__main__':
    main()

trayIcon.setToolTip(u'Тест-проверка')