How to add actions menu in a toolbar?

I want to add a menu from an item in a toolbar. For example, from the following code:

import sys
from PyQt5.QtWidgets import QAction, QMainWindow, QApplication


class Menu(QMainWindow):

    def __init__(self):
        super().__init__()
        colors = QAction('Colors', self)
        exitAct = QAction('Exit', self)

        self.statusBar()
        toolbar = self.addToolBar('Exit')
        toolbar.addAction(colors)
        toolbar.addAction(exitAct)
        self.show()


if __name__ == '__main__':
    app = QApplication(sys.argv)
    menu = Menu()
    sys.exit(app.exec_())

I get:

I want to press on 'Colors' and get a list of options (like Qmenu, but for the toolbar). How can I achieve this?

If you wish to add a QMenu to a QToolBar item you must add a widget that supports it, for example a QPushButton:

import sys
from PyQt5 import QtWidgets


class Menu(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()

        colorButton = QtWidgets.QPushButton("Colors")
        exitAct = QtWidgets.QAction('Exit', self)

        toolbar = self.addToolBar("Exit")

        toolbar.addWidget(colorButton)
        toolbar.addAction(exitAct)

        menu = QtWidgets.QMenu()
        menu.addAction("red")
        menu.addAction("green")
        menu.addAction("blue")
        colorButton.setMenu(menu)

        menu.triggered.connect(lambda action: print(action.text()))


if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    menu = Menu()
    menu.show()
    sys.exit(app.exec_())