def refresh_media_id(self, *args):
'''Updates id numbers for all files in self.media ListProperty'''
mp = {}
for i, x in enumerate(self.media):
x['id'] = i
mpath = x['path']
if mpath in mp:
mp[x['path']].append(i)
else:
mp[x['path']] = [i]
x['playlist_name'] = self.name
if not 'state' in x:
x['state'] = 'normal'
self.media_paths = mp