class emplacement(ModelSQL, ModelView):
    u'Emplacement'
    __name__ = 'cg.emplacement'
    _rec_name = 'code'

    code = fields.Integer(
            string = u'Code emplacement',
            help=u'Code de l\'emplacement',
            required = True,
            states=STATES,
            depends=DEPENDS,
        )

    evolution = fields.One2Many(
            'cg.evol_emplacement',
            'emplacement',
            string=u'Évolutions',
            help=u'Évolutions de l\'emplacement',
            states=STATES,
            depends=DEPENDS,
        )
    number_of_evolutions = fields.Function(
            fields.Integer(
                'Evolutions Nº',
                on_change_with=['evolution']
            ),
            'on_change_with_number_of_evolutions'
        )

    @fields.depends('evolution'):
    def on_change_with_number_of_evolutions(self, name=None):
        return len(self.evolution)

    @staticmethod
    def default_number_of_evolutions():
        return 0

class evol_emplacement(ModelSQL, ModelView):
    u'Évolution d\'un emplacement'
    __name__ = 'cg.evol_emplacement'

    emplacement = fields.Many2One(
            'cg.emplacement',
            string=u'Emplacement',
            help=u'Emplacement',
        )
    compteur = fields.Integer(
                string=u'Number of evolution',
                on_change_with=['emplacement']
            )

    @staticmethod
    def default_compteur():
        return self.emplacement.number_of_evolutions