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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 lam_at_index(self, lidx):
 """Compute the scaled lambda used at index lidx. """

        if self.path_ is None:
            return self.lam * self.lam_scale_

        return self.lam * self.lam_scale_ * self.path_[lidx]