it helps you to update your excel file

excelWork.py

import openpyxl as x
from openpyxl.chart import Reference, BarChart, BarChart3D
i = 0
wb = x.load_workbook("transactions.xlsx")
sheet = wb['Sheet1']
# cell = sheet['a1']
cell = sheet.cell(1, 1)
#print(cell)
z = sheet.max_row
for k in range(2, z+1):

    cell1 = sheet.cell(2+i, 3)
    corrected_price = float(cell1.value * 0.9)
    corrected_price_shell = sheet.cell(2+i, 4)
    corrected_price_shell.value = corrected_price
    i += 1
value = Reference(sheet, min_row = 2,
          max_row=z,
          max_col = 4,
          min_col=4)
chart = BarChart3D()
chart.add_data(value)
sheet.add_chart(chart, 'f6')
#print(value)
wb.save("sak.xlsx")
    # print(cell1.value)