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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _setHeaderLabel(self, col, text):
 """ Sets the header of column col to text. Will increase the number of columns if col is larger than the current number. """

        model = self.tree.model()
        item = model.horizontalHeaderItem(col)
        if item:
            item.setText(text)
        else:
            model.setHorizontalHeaderItem(col, QtGui.QStandardItem(text))