How to create a subprocess "if else" condition

So I created a code that has QLineedit on it and has a Qpushbutton below it. The click.connect pointer includes a subprocess command and it goes like this ( I will only put the click.connect pointer since the QLineedit and Qpushbutton are not that important)

def deluser(self):
    del1 = self.deluserline.text()
    del2 = subprocess.check_output(['userdel',del1)]
    self.deluserline.clear()
    #if a user is deleted, then it should display this:
    self.del3 = QMessageBox()
    self.del3.setText("User deleled !")
    self.del3.setWindowTitle('User delete')
    self.del3.setIcon(QMessageBox.Information)
    self.del3.show()

this actually works. It can delete the user that you will input in the QLineedit but I want to know how to make an if else condition here where if the subprocess actually find a user to delete, it will return the delete success QMessagebox and if it doesnt find a user to delete it will display a 'no user is deleted' prompt.