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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 evaluate(self, batchsize):
 """Evaluate how well the classifier is doing. Return mean loss and mean accuracy"""

        sum_loss, sum_accuracy = 0, 0
        for i in range(0, self.testsize, batchsize):
            x = Variable(self.x_test[i: i + batchsize])
            y = Variable(self.y_test[i: i + batchsize])
            loss = self.model(x, y)
            sum_loss += loss.data * batchsize
            sum_accuracy += self.model.accuracy.data * batchsize
        return sum_loss / self.testsize, sum_accuracy / self.testsize