def _fix_label_alt_id(table):
    """
    Utility that fixes the 'label_alt_id' column to match what is
    expected in the mmCIF format.

    :param table: pandas DataFrame object
    :return: returns a modified pandas DataFrame
    """
    table['label_alt_id'] = table['label_alt_id'].str.replace('\\ |\\?', '.')
    table['label_alt_id'] = table['label_alt_id'].fillna('.').astype(str)
    return table
