class DeliveriesWindowCommunicator(QtCore.QObject):
    refreshDeliveries = QtCore.pyqtSignal()

comm = DeliveriesWindowCommunicator()

class CourierMenu(QtGui.QWidget):
    def initUI(self):
        self.deliveriesComm = deliveriesWidget.comm
        self.deliveriesComm.refreshDeliveries.connect(self.refreshDeliveries)
        ...

    def refreshDeliveries(self):
        deliveriesMenu = deliveriesWidget.DeliveriesMenu(self.openDeliveries)
        ...

class DeliveriesMenu(QtGui.QWidget):
    def initUI(self, username):
        comm.refreshDeliveries.connect(self.close)
    ...

class AddDeliveryWidget(QtGui.QDialog):
    def initUI(self,username):
        addButton = QtGui.QPushButton('OK')
        addButton.clicked.connect(lambda: self.addCourier(str(courierId[0]),str(address.toPlainText()),str(latlng.toPlainText()),
            str(packageId.toPlainText()),str(comm.cachedDate),
            str(receiver.toPlainText()),str(phone.toPlainText()),
            str(sender.toPlainText()),str(extra.toPlainText()),
            str(status.toPlainText())))
        ...

    def addCourier(self, courierId, address, latlng, packageId, deliveryTime, receiver, phone, sender, extra, status):
        dbHelper.create_delivery((courierId, address, latlng, packageId, deliveryTime, receiver, phone, sender, extra, status))
        comm.refreshDeliveries.emit()
        self.close()