if you would like to do custom rendering for each row of the two dimensional datayou would need to pass row formatting/rendering function to the parameter "rendererof pyexcel' signature functions __init__(namepayloadinitialize self see help(type(self)for accurate signature methods __init__(namepayloadget_internal_array(to_array(initialize self simply return the generator attributes array array attribute pyexcel internal generators bookstream class pyexcel internal generators bookstream(sheets=nonepath=nonememory efficient book representation filename='memory'comparing with pyexcel bookthe instace of this class uses pyexcel generators sheetstream as its internal repesentation of sheet objects because sheetstream does not read data into memoryit is memory efficient __init__(sheets=nonefilename='memory'path=nonebook constructor selecting specific book according to filename extension :param ordereddict/dict sheetsa dictionary of data :param str filenamethe physical file :param str paththe relative path or absolute path :param set keywordsadditional parameters to be passed on methods __init__([sheetsfilenamepath]load_from_sheets(sheetsnumber_of_sheets(sheet_names(to_dict(book constructor load content from existing sheets return the number of sheets get book data structure as dictionary row representation row(matrixrepresent row of matrix pyexcel internal sheets row class pyexcel internal sheets row(matrixrepresent row of matrix support the project