def _save(tables, writer, sheet_name='Sheet1', n_row=1):
    """Save a list of tables as an excel file.
    
    Parameters
    ----------
    tables : iterable[DataFrame]
    writer : ExcelWritter
        
    """
    for t in tables:
        label = t.columns.name
        t.to_excel(writer, sheet_name, startrow=n_row, index_label=label)
        n_row += len(t.index) + 2
    return n_row
