title: Pyqt5 updated Widget is not added to the layout though the widget is updated
body: <p>I am trying to show set of actions when a button is clicked and other set of options if another button is clicked.
  Below is the code:</p>
  
  <pre><code>  class Screen(QWidget):
      def __init__(self):
          super(Screen, self).__init__()
          layout = QHBoxLayout(self)
          self.all_running()
          layout.addWidget(self.running_full_widget)
          self.actions('1')
          layout.addWidget(self.actions_full_widget)
          self.setLayout(layout)
          self.show()
      def all_running(self):
          self.running_full_widget = QWidget()
          runnning_full_layout= QVBoxLayout()
          button1 = QPushButton("btn1")
          button2 = QPushButton("btn2")
          button1.clicked.connect(lambda: self.actions('2'))
          button2.clicked.connect(lambda: self.actions('3'))
          runnning_full_layout.addWidget(button1)
          runnning_full_layout.addWidget(button2)
          self.running_full_widget.setLayout(runnning_full_layout)
      def actions(self,value):
          self.actions_full_widget= QWidget()
          val = int(value)
          print(val)
          actions_layout = QVBoxLayout()
          for i in range(val):
             actions_item = QLabel(str(i))
             actions_layout.addWidget(actions_item)
          self.actions_full_widget.setLayout(actions_layout)
  
  app = QApplication(sys.argv)
  Gui = Screen()
  sys.exit(app.exec_())
  </code></pre>
  
  <p>When button is clicked i can see the value is updated but it is not updated in the main layout. 
  how can i dynamically update the widgets ?
  How can I do that in cases where i need to add widgets based on a dynamic value.
  did i miss anything with signals and slots?
  Kindly correct me if i am wrong. Thanks</p>