How to use the omegaml.util.restore_index function in omegaml

meta_columns = dict(meta.kind_meta.get('columns'))
            if meta_columns:
                # apply projection, if any
                if columns:
                    # get only projected columns
                    # meta_columns is {origin_column: stored_column}
                    orig_columns = dict({k: v for k, v in iteritems(meta_columns)
                                         if k in columns or v in columns})
                else:
                    # restore columns to original name
                    orig_columns = meta_columns
                df.rename(columns=orig_columns, inplace=True)
            # -- restore indexes
            idx_meta = meta.kind_meta.get('idx_meta')
            if idx_meta:
                df = restore_index(df, idx_meta)
            # -- restore row order
            if is_series:
                index = df.index
                name = df.columns[0]
                df = df[name]
                df.index = index
                df.name = None if name == 'None' else name
        return df

def _restore_dataframe_proper(self, df):
        df = restore_index(df, dict())
        if '_id' in df.columns:
            df.drop('_id', axis=1, inplace=True)
        if self.force_columns:
            missing = set(self.force_columns) - set(self.columns)
            for col in missing:
                df[col] = np.NaN
        return df

def evaluate(self):
        """
        evaluate the query

        :return: the pandas DataFrame
        """
        result = self.q.apply_filter(self.coll)
        try:
            import pandas as pd
            result = pd.DataFrame.from_records(result)
            if '_id' in result.columns:
                del result['_id']
            result = restore_index(result, dict(),
                                   rowid_sort=not self.q.sorted)
        except ImportError:
            result = list(result)
        return result