primitive procedure to rename a bunch of files that broke with naming convention

file_renamer.py

import shutil, os

current_directory = os.getcwd()
filename = 'output.txt'

for file in os.listdir(current_directory):
    active = file.replace('_idle', '_act')
    print(active)
    if '_idle' in file and not os.path.isfile(active):
        output = file.replace('_idle','_act')
        source = file.replace('_idle','')
        with open(filename, 'a') as f:
            f.write(output)
            f.write(",\n")
        if os.path.isfile(source):
            shutil.copy(source, active)
        else:
            pass
        shutil.copy(file,source)
        os.remove(file)
    else:
        pass