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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 targeting_criteria(self, id=None, **kwargs):
 """ Returns a collection of targeting criteria available to the current line item. """

        self._validate_loaded()
        if id is None:
            return TargetingCriteria.all(self.account, self.id, **kwargs)
        else:
            return TargetingCriteria.load(self.account, id, **kwargs)