title: PyQt's Signal / SLOT different classes
body: <p>can i connect two objects that are in different classes ?</p>
  
  <p>lets say i want button1's clicked() signal  to clear line2</p>
  
  <pre><code>class A(QGroupBox):
      def __init__(self, parent=None):
          super(A, self).__init__(parent)
          self.button1= QPushButton('bt1')
          self.button1.show()
  
  class B(QGroupBox):
      def __init__(self, parent=None):
          super(B, self).__init__(parent)
          self.line2 = QLineEdit()
          self.line2.show()
  
  ob1 = A()
  ob2 = B()
  </code></pre>