how to activate SizeGrip in QMainWindow

I would like to know how I can activate the SizeGrip in the qmainwindow, but without the status bar in the MainWindow.

this is what I have done:

from PyQt5.QtWidgets import QMainWindow,QApplication
from PyQt5 import QtCore



class Principal(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)

        self.setWindowFlags(QtCore.Qt.FramelessWindowHint)
        self.setSizeGripEnabled(True)





app  =QApplication([])
p = Principal()
p.resize(900,600)
p.show()
app.exec_()