if add_metadata:
                # Warn if there are duplicated keys in metadata compared to the existing features
                # (`BASE_COLUMN_NAME`, optionally "label")
                duplicated_keys = set(self.info.features) & set(metadata_features)
                if duplicated_keys:
                    logger.warning(
                        f"Ignoring metadata columns {list(duplicated_keys)} as they are already present in "
                        f"the features dictionary."
                    )
                # skip metadata duplicated keys
                self.info.features.update(
                    {
                        feature: metadata_features[feature]
                        for feature in metadata_features
                        if feature not in duplicated_keys
                    }
                )

        return splits