问MemoryError .没有提供异常消息

EN

@python_2_unicode_compatible
class Mot(BaseModel):
    groupes_categories = models.ManyToManyField(GroupeCategories, blank=True,
                                                through='MotGroupeCategories',
                                                symmetrical=False,
                                                related_name='mot')
    texte = models.CharField(max_length=150)

    def __str__(self):
        return _(u'{}').format(self.texte)


@python_2_unicode_compatible
class GroupeCategories(models.Model):
    description = models.CharField(max_length=150)
    exemple = models.CharField(max_length=150, blank=True, default=None,
                               null=True)

    def __str__(self):
        return _(u'{0}{1}').format(
            self.description,
            u' ({0})'.format(self.exemple) if self.exemple else u''
        )


@python_2_unicode_compatible
class MotGroupeCategories(models.Model):
    mot = models.ForeignKey(Mot, blank=False)
    groupe_categories = models.ForeignKey(GroupeCategories, blank=False)

    def __str__(self):
        return u'{} - {}'.format(self.mot.texte,
                                 self.groupe_categories.description)

class MotGroupeCategoriesAdmin(admin.ModelAdmin):

    def mot_texte(self, obj):
        return obj.mot.texte
    mot_texte.allow_tags = True
    mot_texte.short_description = _(u'I.')

    fields = ('mot', 'groupe_categories')
    list_display = ('groupe_categories', 'mot_texte', 'id')
    list_display_links = list_display
    search_fields = ['description']


admin.site.register(MotGroupeCategories, MotGroupeCategoriesAdmin)

/admin/main/motgroupecategories/[id]/

MemoryError at /admin/main/motgroupecategories/12060915/
No exception message supplied
Request Method: GET
Request URL:        /admin/main/motgroupecategories/[id]/
Django Version: 1.8.7
Exception Type: MemoryError
Exception Location: C:\Python27\lib\site-packages\django\forms\widgets.py
    in render_options, line 547