Python 3.13.4 Renamer [Warning!]

Careful with this script! If used properly it will rename all files extensions in current directory and subdirectories!

import os,sys
c = 0
#filename = "list_of_renamed_file_exts.txt"
#f = open(filename,"w")
for i in os.walk("."):
    for j in i[2]:
        if j == "renamer.py":
            continue
        if j.endswith(".py"):
            c += 1
            filestr = str(c)+": "+i[0]+"\\"+j
#           f.write(filestr+"\n")
            print(filestr)
#           os.rename(i[0]+"\\"+j,i[0]+"\\"+j+".new_ext")
#           print(filestr + " renamed!")
#f.close()