#!/usr/bin/env python
# -*- coding: utf-8 -*-

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


class MyWindow(QMainWindow):
    def __init__(self):
        super(MyWindow, self).__init__()
        self.setGeometry(200, 200, 300, 300)
        self.setWindowTitle('Here is the window')
        self.initUI()

    def initUI(self):
        self.label = QtWidgets.QLabel(self)
        self.label.setText('My first label!')
        self.label.move(49,50)

        self.b0 = QtWidgets.QPushButton(self)
        self.b0.setText('Click here')
        self.b0.clicked.connect(self.clicked)

    def clicked(self):
        self.label.setText('you pressed the button')
        self.update()

    def update(self):
        self.label.adjustSize()

def clicked():
    print('clicked')

def window():
    app = QApplication(sys.argv)
    win = MyWindow()
    win.show()
    sys.exit(app.exec_())


window()