`compute_extra` plante s'il n'y a pas de clone

Traceback (most recent call last):
  File "/home/vidjil/git/server/vidjil/server/web2py/gluon/scheduler.py", line 501, in executor
    result = dumps(_function(*args, **vars))
  File "applications/vidjil/models/task.py", line 331, in run_vidjil
    compute_extra(id_file, id_config, 5)
  File "applications/vidjil/models/task.py", line 111, in compute_extra
    for clone in d["clones"]:
TypeError: 'NoneType' object is not iterable