plotting multiple values
            >>> import torch
            >>> from torchmetrics.clustering import DunnIndex
            >>> metric = DunnIndex(p=2)
            >>> values = [ ]
            >>> for _ in range(10):
            ...     values.append(metric(torch.randn(10, 3), torch.randint(0, 2, (10,))))
            >>> fig_, ax_ = metric.plot(values)

        )