code: def mean_squared_error(pred:Tensor, targ:Tensor)->Rank0Tensor:
      "Mean squared error between `pred` and `targ`."
      pred,targ = flatten_check(pred,targ)
      return F.mse_loss(pred, targf mean_squared_error(pred:Tensor, targ:Tensor)->Rank0Tensor:
      "Mean squared error between `pred` and `targ`."
      pred,targ = flatten_check(pred,targ)
      return F.mse_loss(pred, targ)
docs: Mean squared error between `pred` and `targ`.