modify models.py
modify models.py

lsaffre/lino,lino-framework/lino,lsaffre/lino,khchine5/lino,lsaffre/lino,lino-framework/lino,lino-framework/lino,khchine5/lino,khchine5/lino,lsaffre/lino,lino-framework/lino,lino-framework/lino,lsaffre/lino,khchine5/lino,khchine5/lino