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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 default(self):
 """Default value of the property"""

        prop_def = getattr(self, '_default', utils.undefined)
        for prop in self.props:
            if prop.default is utils.undefined:
                continue
            if prop_def is utils.undefined:
                prop_def = prop.default
                break
        return prop_def