How can use different font & size for the child Widgets in the GroupBox and the tittle for the GroupBox in python 

```
def panel(self):
    groupBox = QtGui.QGroupBox("voltage Monitor")
    groupBox.setFont(QtGui.QFont('SansSerif', 13))       # the title size is good
    ..

    self.Voltage_Label = []
    ..

    vbox = QtGui.QGridLayout()
    self.Voltage_Label.append(QtGui.QLabel("voltage1 ")) # i need to have diff Font & size for these 
    self.Voltage_Label.append(QtGui.QLabel("voltage2 "))   
    self.Voltage_Label.append(QtGui.QLabel("voltage3 ")) 
    ..
    vbox.addWidget(self.Voltage_Label[i], i, 0)  
    ..
    groupBox.setLayout(vbox)
    return groupBox

```

I tired this 

```
   self.Voltage_Label.setFont(QtGui.QFont('SansSerif', 10))

```

I get this error 

```
    !! self.Voltage_Label.setFont(QtGui.QFont('SansSerif', 10))
AttributeError: 'list' object has no attribute 'setFont' !!

```

but for something like this`title1 = QtGui.QLabel("Sample Title")` as a child widget i can change it by 

```
 title1.setFont(QtGui.QFont('SansSerif', 10))

```