Friends Blueray rename script

from os import rename, listdir

found = set()

def read_dictionary():
  mydict = {}
  with open('dictionary.txt', 'r') as dict_file:
    for line in dict_file:
      line = line.strip()
      split_line = line.split('|')
      mydict[split_line[1]] = split_line[0]+'.mkv'
  return mydict

def rename_files(files, rename_dict):
  for fname in fnames:
    if fname in rename_dict:
      print(fname, '->', rename_dict[fname])
      rename(fname, rename_dict[fname])

def validate(fnames, mydict):
    files_set = set(fnames)
    missing = mydict.keys() - files_set
    lmissing = list(missing)
    lmissing.sort()
    for m in lmissing:
        print('missing expected file', m)
    if lmissing:
        raise Exception('missing expected files')

mydict = read_dictionary()
fnames = listdir('.')
validate(fnames, mydict)
rename_files(fnames, mydict)