a = ['January\n', 'February\n', 'March\n', 'April\n', 'May\n', 'June\n']
xbook = xlsxwriter.Workbook('Test.xlsx')
xsheet = xbook.add_worksheet('Test')
xsheet.write_row(0, 0, a)
xbook.close()
xlsxwriter и xlwt: запись списка строк в ячейку