old_contents: #!/usr/bin/env python3
  # -*- coding: utf-8 -*-
  
  # Copyright (c) 2015 Jérémie DECOCK (http://www.jdhp.org)
  
  # Permission is hereby granted, free of charge, to any person obtaining a copy
  # of this software and associated documentation files (the "Software"), to deal
  # in the Software without restriction, including without limitation the rights
  # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  # copies of the Software, and to permit persons to whom the Software is
  # furnished to do so, subject to the following conditions:
  
  # The above copyright notice and this permission notice shall be included in
  # all copies or substantial portions of the Software.
   
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  # THE SOFTWARE.
  
  import sys
  from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton
  
  
  class Window(QMainWindow):
      def __init__(self):
          super().__init__()
  
          self.resize(250, 150)
          self.setWindowTitle('Hello')
  
          button = QPushButton('Hello', self)
          button.clicked.connect(self.on_clic)
  
          self.show()
  
      def on_clic(self):
          print("Hello!")
  
  
  app = QApplication(sys.argv)
  
  window = Window()
  
  exit_code = app.exec_()
  sys.exit(exit_code)
  
new_contents: #!/usr/bin/env python3
  # -*- coding: utf-8 -*-
  
  # Copyright (c) 2015 Jérémie DECOCK (http://www.jdhp.org)
  
  # Permission is hereby granted, free of charge, to any person obtaining a copy
  # of this software and associated documentation files (the "Software"), to deal
  # in the Software without restriction, including without limitation the rights
  # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  # copies of the Software, and to permit persons to whom the Software is
  # furnished to do so, subject to the following conditions:
  
  # The above copyright notice and this permission notice shall be included in
  # all copies or substantial portions of the Software.
   
  # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  # THE SOFTWARE.
  
  import sys
  from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton
  
  
  class Window(QMainWindow):
      def __init__(self):
          super().__init__()
  
          button = QPushButton('Hello', self)
          button.clicked.connect(self.on_clic)
  
      def on_clic(self):
          print("Hello!")
  
  
  app = QApplication(sys.argv)
  
  window = Window()
  window.show()
  
  exit_code = app.exec_()
  sys.exit(exit_code)
  
subject: Simplify a snippet.