FileNotFoundError: [Errno 2] No such file or directory: '/workdir/messy/messy'

import os

# Filenames consist of a username (alphanumeric, 3-12 characters)
# and a date (four digit year, two digit month, two digit day),
# and an extension. They should end up in the format
# year-month-day-username.extension.

# Example: kennethlove2-2012-04-29.txt becomes 2012-04-29-kennethlove2.txt

def cleanup(path):
    # your code here
    os.chdir(path)
    for f in os.listdir():
        f_name, f_ext = os.path.splitext(f)
        #print(f_name, f_ext)
        f_title, f_d1, f_d2, f_d3 = f_name.split('-')
        #print(f_title, f_d1, f_d2, f_d3)
        #print('{}-{}-{}-{}{}'.format(f_d1, f_d2, f_d3, f_title, f_ext))
        new_name = '{}-{}-{}-{}{}'.format(f_d1, f_d2, f_d3, f_title, f_ext)
        #print(new_name)
        os.rename(f, new_name)