     to the parameters of :class:`AveragedModel`. For every subsequent
        call of :meth:`update_parameters` the function `avg_fn` is used
        to update the parameters.

    .. _Averaging Weights Leads to Wider Optima and Better Generalization:
        https://arxiv.org/abs/1803.05407
    .. _There Are Many Consistent Explanations of Unlabeled Data: Why You Should
        Average:
        https://arxiv.org/abs/1806.05594
    .. _SWALP: Stochastic Weight Averaging in Low-Precision Training:
        https://arxiv.org/abs/1904.11943
    .. _Stochastic Weight Averaging in Parallel: Large-Batch Training That
        Generalizes Well:
        https://arxiv.org/abs/2001.02312
    NFc