I'm trying to make a new 'Qradiobutton' when I click on create button... but the button creates just one Qradiobutton. any advice ???

my code:

```py
import sys
from PyQt5.QtWidgets import (
    QApplication, QMainWindow, QWidget, QPushButton, QRadioButton
)

class main(QMainWindow):
    def __init__(self):
        super().__init__()

        self.newUi()

        self.setGeometry(400, 400, 500, 500)
        self.setWindowTitle('Create')
        self.show()

        self.radio1 = QRadioButton('first', self)
        self.radio1.setGeometry(50, 50, 60, 20)

        self.radio2 = QRadioButton('second', self)
        self.radio2.setGeometry(50, 90, 60, 20)

        self.radio3 = QRadioButton('third', self)
        self.radio3.setGeometry(50, 130, 60, 20)

    def newUi(self):
        self.btn = QPushButton('create', self)

        self.btn.clicked.connect(self.create)

    def create(self):
        n = 1

        if n == 1:
            self.radio1.show()
            n = 2

        elif n == 2:
            self.radio2.show()
            n == 3

        elif n == 3:
            self.radio3.show()

        else:
            print('done')

if __name__ == "__main__":
    app = QApplication(sys.argv)
    e = main()
    app.exec()

```