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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 _write_avg_gradient(self)->None:
        "Writes the average of the gradients to Tensorboard."
        avg_gradient = sum(x.data.mean() for x in self.gradients)/len(self.gradients)
        self._add_gradient_scalar('avg_gradient', scalar_value=avg_gradient)