How to change font size of child QLabel widget from the groupBox

Question

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 thistitle1 = QtGui.QLabel("Sample Title") as a child widget i can change it by

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

Answer 1

While I was waiting for an answer I wanted to give it a try and found this method/solution for my question:

self.Voltage_Label = []

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 "))
.
.

for i in xrange(5):
        newfont = QtGui.QFont("Times", 8, QtGui.QFont.Bold) 
        self.Voltage_Label[i].setFont(newfont)