python之Django: ManyToManyField 未定义错误

我一直在尝试在 django-userena 中编辑用户配置文件，除了我的 ManyToManyFields 之外，一切都很好。我设置了以下模型:

class MyProfile(UserenaBaseProfile): 
    user = models.OneToOneField(User,unique=True,   
                        verbose_name=_('user'),related_name='my_profile') 
    favourite_snack = models.CharField(_('favourite snack'),max_length=5)  
    firstname = models.CharField(_('username'), max_length=55) 
    lastname = models.CharField(_('lastname'), max_length=66) 
    industry = models.CharField(_('industry'), max_length=190) 
    occupation = models.CharField(_('occupation'), max_length=140) 
    bio = models.TextField(_('bio')) 
    phone = models.CharField(_('phone'), max_length=10) 
    skills = models.ManyToManyField(Skills) 
    Interests = models.ManyToManyField(Interests) 
    website = models.URLField() 
 
class Skills(models.Model): 
    skillName = models.CharField(max_length=80) 
 
class Interests(models.Model): 
    interestName = models.CharField(max_length=140) 

当我同步数据库时，出现以下错误:

 File "/pathtodjango/bin/app/accounts/models.py", line 17, in MyProfile 
    skills = models.ManyToManyField(Skills) 
NameError: name 'Skills' is not defined 

请您参考如下方法:

使用惰性引用:

skills = models.ManyToManyField('Skills')