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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 defaultData(self, defaultData):
 """ Sets the data of this item. Does type conversion to ensure default data is always of the correct type. """

        self._defaultData = self._enforceDataType(defaultData) # Enforce to be a QFont
        self.familyCti.defaultData = fontFamilyIndex(self.defaultData,
                                                     list(self.familyCti.iterConfigValues))
        self.pointSizeCti.defaultData = self.defaultData.pointSize()
        self.weightCti.defaultData = self.defaultData.weight()
        self.italicCti.defaultData = self.defaultData.italic()