Replace SI-SNR loss with MSE loss

I have a loss function called SI-SNR loss function implemented as follows:

def si_snr_loss(ests, egs):
    refs = egs["ref"]
    num_spks = len(refs)

    def sisnr_loss(permute):
        return sum([sisnr(ests[s], refs[t]) for s, t in enumerate(permute)]) / len(permute)
    N = egs["mix"].size(0)
    sisnr_mat = torch.stack([sisnr_loss(p) for p in permutations(range(num_spks))])
    max_perutt,_ = torch.max(sisnr_mat, dim=0)
    return -torch.sum(max_perutt) / N

I want to replace this loss function with an MSE loss function I write a simple equation as follows:

for egs in val_dataloader:

            current_step += 1

            egs = to_device(egs, self.device)

            ests = data_parallel(self.net, egs['mix'], device_ids=self.gpuid)
            #loss = si_snr_loss(ests, egs)
            loss = (ests - torch.Tensor(np.array(egs.values())))**2
            losses.append(loss.item())

Unfortunately, this gives me an error:
TypeError: can’t convert np.ndarray of type numpy.object_. The only supported types are: float64, float32, float16, int64, int32, int16, int8, uint8, and bool.

The error seems to be raised by numpy in:

np.array(egs.values())

Based on the error message it seems that egs.values() might return objects with variable shapes or any other objects which numpy cannot transform to an array.
Could you print this object and check what is stored in it?