how to send a message to pyqt5 python qmainwindow code example

Example: pyqt5 message box

# in pyqt5 it needs to be PyQt5.QtWidgets
msg=QMessageBox() # create an instance of it
msg.setIcon(QMessageBox.Information) # set icon
msg.setText("This is a message box") # set text
msg.setInformativeText("This is additional information") # set information under the main text
msg.setWindowTitle("MessageBox demo") # set title
msg.setDetailedText("The details are as follows:") # a button for more details will add in
msg.setStandardButtons(QMessageBox.Ok | QMessageBox.Cancel) # type of buttons associated
msg.buttonClicked.connect(myfunc) # connect clicked signal
return_value =msg.exec_() # get the return value
print("value of pressed message box button:", str(return_value)) # print result