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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 returns(self, obj):
 """ Customizes the return values of the stub function. If conditions like withArgs or onCall were specified, then the return value will only be returned when the conditions are met. Args: obj (anything) Return: a SinonStub object (able to be chained) """

        self._copy._append_condition(self, lambda *args, **kwargs: obj)
        return self