def soft_update(target: nn.Module, source: nn.Module, tau: float) -> None:
    """Updates the `target` data with the `source` one
    smoothing by ``tau`` (inplace operation).

    Args:
        target: nn.Module to update
        source: nn.Module for updating
        tau: smoothing parametr

    """
    for target_param, param in zip(target.parameters(), source.parameters()):
        target_param.data.copy_(target_param.data * (1.0 - tau) + param.data * tau)
Updates the `target` data with the `source` one
    smoothing by ``tau`` (inplace operation).

    Args:
        target: nn.Module to update
        source: nn.Module for updating
        tau: smoothing parametr

    
catalyst/utils/torch.py