class myGUI(QtGui.QWidget):

    def __init__(self, *args, **kwargs):
        QtGui.QWidget.__init__(self, *args, **kwargs)
self.data = {'multiplier': 0, 'multiplicand': 0}
self.myGUIInit()

def myGUIInit(self):
    a1_label = QtGui.QLabel('a1')
a1_edit = QtGui.QLineEdit()
a1_edit.setObjectName('multiplicand')
a2_label = QtGui.QLabel('a2')
a2_edit = QtGui.QLineEdit()
a2_edit.setObjectName('multiplier')

def TxtChanged(self, text):
    sender = self.sender()
self.data[sender.objectName()] = int(text)
product = self.data['multiplier'] * self.data['multiplicand']
print((self.data['multiplier'], self.data['multiplicand'], product))
self.a1a2_edit.setText(str(product))
Differentiating between signal sources in PySide