@abc.abstractmethod<EOL><INDENT>def write_cells(self, cells, sheet_name=None, startrow=<NUM_LIT:0>, startcol=<NUM_LIT:0>,<EOL>freeze_panes=None):<DEDENT>
pass<EOL>
Write given formatted cells into Excel an excel sheet

Parameters
----------
cells : generator
    cell of formatted data to save to Excel sheet
sheet_name : string, default None
    Name of Excel sheet, if None, then use self.cur_sheet
startrow : upper left cell row to dump data frame
startcol : upper left cell column to dump data frame
freeze_panes: integer tuple of length 2
    contains the bottom-most row and right-most column to freeze