Saves `adata_raw` to a .h5ad file (AnnData's native file format).

        Parameters
        ----------
        fname - string
            The filename of the output file.

def save_anndata(self, fname, data = 'adata_raw', **kwargs):
        """Saves `adata_raw` to a .h5ad file (AnnData's native file format).

        Parameters
        ----------
        fname - string
            The filename of the output file.

        """
        x = self.__dict__[data]
        x.write_h5ad(fname, **kwargs)