Copying range from one excel to another

Question

I am trying to copy a range form one excel sheet to another. This is my code:

import openpyxl
import os

#Current path
path = os.path.dirname(os.path.abspath(__file__))

#Beregningsmodul navn
Beregningsmodul_moder = "Beregning COREP LCR - MODER - 202202.xlsx"

#Skema 72 navn
workbook_skema_72 ="C_72_00_a.xlsx"

#workbook_beregn path
workbook_beregn_path = path + "\\" + Beregningsmodul_moder
workbook_beregn = openpyxl.load_workbook(workbook_beregn_path)

#Kopier til
wb_72C = workbook_beregn["72C"]['E8':'G54']

#kopier fra
C_72_00_a = workbook_skema_72["C_72_00_a"]['D9':'F55']

#Pair the rows
for row1,row2 in zip(C_72_00_a, workbook_beregn):
    #within the row pair, pair the cells
    for cell1, cell2 in zip(row1,row2):
        #assign the value of cell 1 to the destination cell 2 for each row
        cell2.value = cell1.value
#save document
workbook_beregn.save('destination.xlsx')

But I get this error:

C_72_00_a = workbook_skema_72["C_72_00_a"]['D9':'F55']
TypeError: string indices must be integers

Am I defining the ranges in a wrong way or something? I hope you can point me in the right direction.