Accessing Custom Widget In Python Qt?

Studying online examples I managed to get a custom widget added to a listbox in PyQT4, this is the code for the custom widget progress.py:

from PyQt4 import QtCore, QtGui, QtWebKit

try:
    _fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
    def _fromUtf8(s):
        return s

try:
    _encoding = QtGui.QApplication.UnicodeUTF8
    def _translate(context, text, disambig):
        return QtGui.QApplication.translate(context, text, disambig, _encoding)
except AttributeError:
    def _translate(context, text, disambig):
        return QtGui.QApplication.translate(context, text, disambig)

class Ui_(QtGui.QWidget):
    def __init__(self, name, parent=None):
        super(QtGui.QWidget,self).__init__(parent)
        self.layoutWidget = QtGui.QWidget()
        self.layoutWidget.setGeometry(QtCore.QRect(0, 0, 611, 31))
        self.layoutWidget.setObjectName(_fromUtf8("layoutWidget"))
        self.gridLayout = QtGui.QGridLayout(self.layoutWidget)
        self.gridLayout.setMargin(0)
        self.gridLayout.setSpacing(10)
        self.gridLayout.setObjectName(_fromUtf8("gridLayout"))

        self.progressBar = QtGui.QProgressBar(self.layoutWidget)
        self.progressBar.setProperty("value", 0)
        self.progressBar.setObjectName(_fromUtf8("progressBar"))
        self.gridLayout.addWidget(self.progressBar, 0, 1, 1, 1)
        self.gridLayout.addWidget(self.graphicsView, 1, 1, 1, 1)

        self.webView = QtWebKit.QWebView(self.layoutWidget)
        self.webView.setGeometry(QtCore.QRect(0, 0, 500, 200))
        self.webView.setUrl(QtCore.QUrl(_fromUtf8("about:blank")))
        self.webView.setObjectName(_fromUtf8("webView"))
        self.gridLayout.addWidget(self.webView, 1, 1, 1, 1)


        QtCore.QMetaObject.connectSlotsByName(self)
        #self.label.setText(_translate("", name, None))
        self.webView.setHtml(name)
        self.setLayout(self.gridLayout)

I am using the below code to add and populate this custom widget from main.py as:

def on_info_ready(self, data):
      info = data.split("\n")
      item = QtGui.QListWidgetItem(self.ui.listWidget)
      makeHtml = "<h1>" + info[1] + "</h1>"
      item_widget = progress.Ui_(makeHtml)
      item.setSizeHint(item_widget.sizeHint())
      self.ui.listWidget.addItem(item)
      self.ui.listWidget.setItemWidget(item,item_widget)

The above works perfectly, but I am unable to figure out how to access the progressbar control in above added custom widget appended as listitems. I tried multiple variations of the below but it fails :

  def on_progress(self, data):
      print (data)
      self.ui.listWidget.item(0).progressBar.setValue(data)

The above code errors out as :

Traceback (most recent call last):
  File "C:\Users\kk\Desktop\py4 gui\main.py", line 105, in on_progress
    self.ui.listWidget.item(0).progressBar.setValue(data)
AttributeError: 'QListWidgetItem' object has no attribute 'progressBar'
0.0
Traceback (most recent call last):
  File "C:\Users\kk\Desktop\py4 gui\main.py", line 105, in on_progress
    self.ui.listWidget.item(0).progressBar.setValue(data)
AttributeError: 'QListWidgetItem' object has no attribute 'progressBar'
0.0