combine Excel all code

import os
import glob
import pandas as pd

if os.path.exists('output.xlsx'):
    os.remove('output.xlsx')

all_excel_files = [i for i in glob.glob('*.xlsx')]

holder_list = list()

for i in range(len(all_excel_files)):
    cfile = pd.read_excel(all_excel_files[i])
    cfile.insert(0, "file_name", all_excel_files[i])
    holder_list.append(cfile)

df = pd.concat(holder_list)

df.to_excel('output.xlsx', index=False)