PyQt - Implement a QAbstractTableModel for display in QTableView

I would like to display a pandas data frame in a PyQt table. I have made some progress with this, but have not been able to correctly derive the Table Model class. Any help with this would be much appreciated.

** Note full example code here **

I am struggling to generate a valid QtCore.QAbstractTableModel derived class. Following on from a previous question about QItemDelegates I am trying to generate a table model from a Pandas DataFrame to insert real data. I have working example code here, but if I replace my TableModel with TableModel2 in the Widget class (ln 152) I cannot get the table to display.

class TableModel2(QtCore.QAbstractTableModel): 
    def __init__(self, parent=None, *args): 
        super(TableModel2, self).__init__()
        #QtCore.QAbstractTableModel.__init__(self, parent, *args)
        self.datatable = None
        self.headerdata = None
        self.dataFrame = None
        self.model = QtGui.QStandardItemModel(self)

    def update(self, dataIn):
        print 'Updating Model'
        self.datatable = dataIn
        print 'Datatable : {0}'.format(self.datatable)
        headers = dataIn.columns.values
        header_items = [
                    str(field)
                    for field in headers
        ]
        self.headerdata = header_items
        print 'Headers'
        print self.headerdata

        for i in range(len(dataIn.index.values)):
            for j in range(len(dataIn.columns.values)):
                #self.datatable.setItem(i,j,QtGui.QTableWidgetItem(str(df.iget_value(i, j))))
                self.model.setItem(i,j,QtGui.QStandardItem(str(dataIn.iget_value(i, j))))

    def rowCount(self, parent=QtCore.QModelIndex()):
        return len(self.datatable.index) 

    def columnCount(self, parent=QtCore.QModelIndex()):
        return len(self.datatable.columns.values)