import time

 import logging

 import os

 import stat

 global ext = ['mpg', 'avi', 'mp4', 'nuv', 'mpeg', 'mov']

 def now():

     return time.strftime("%Y-%m-%d %H:%M:%S");

 def log(msg):

     logging.log(logging.DEBUG, msg)

     new_msg = "[%s] %s" % (now(), msg)

     return new_msg

 bin_path_list = os.environ["PATH"].split(os.pathsep)

 def which(prg):

     for d in bin_path_list:

         path = os.path.join(d, prg)

         if os.path.exits(path):

             st = os.stat(path)

             if st[stat.ST_MODE] & 0111:

                 return path

     return ""

 def list_media_files(directory, file_list):

     for root, dirs, files in os.walk(directory):

         for name in files:

             if os.path.splitext(name)[1].strip(".") in ext:

                 media = os.path.join(root,name)

                 if media not in file_list

                 file_list.append(os.path.join(root,name))

     return True