Filepath for mmcif file associated with code.

        Notes
        -----
        Downloads mmcif file if not already present.

        Returns
        -------
        mmcif_file : str
            Filepath for the mmcif file.

def mmcif(self):
        """ Filepath for mmcif file associated with code.

        Notes
        -----
        Downloads mmcif file if not already present.

        Returns
        -------
        mmcif_file : str
            Filepath for the mmcif file.
        """
        mmcif_dir = os.path.join(self.parent_dir, 'mmcif')
        if not os.path.exists(mmcif_dir):
            os.makedirs(mmcif_dir)
        mmcif_file_name = '{0}.cif'.format(self.code)
        mmcif_file = os.path.join(mmcif_dir, mmcif_file_name)
        if not os.path.exists(mmcif_file):
            get_mmcif(code=self.code, outfile=mmcif_file)
        return mmcif_file