Convert prior samples to xarray.

def prior_to_xarray(self):
        """Convert prior samples to xarray."""
        # filter prior_predictive
        prior_predictive = self.prior_predictive
        columns = self.prior[0].columns
        if prior_predictive is None or (
            isinstance(prior_predictive, str) and prior_predictive.lower().endswith(".csv")
        ):
            prior_predictive = []
        elif isinstance(prior_predictive, str):
            prior_predictive = [col for col in columns if prior_predictive == col.split(".")[0]]
        else:
            prior_predictive = [
                col
                for col in columns
                if any(item == col.split(".")[0] for item in prior_predictive)
            ]

        invalid_cols = prior_predictive
        valid_cols = [col for col in columns if col not in invalid_cols]
        data = _unpack_dataframes([item[valid_cols] for item in self.prior])
        return dict_to_dataset(data, coords=self.coords, dims=self.dims)