Django Newbie ManyRelated Manager not Iterable Question

I'm trying to create a product code (in the admin) by combining elements from two other fields - one of which is a ManyToManyField. I'd like to iterate through that field to find out if a specific product option has been chosen, and append a variation of it to that non-editable product code, like so: ``` class ShirtColorClass(models.Model): shirtcolor = models.CharField(_('Shirt Color'), unique=True, max_length=40) def __unicode__(self): return self.shirtcolor class ShirtClass(models.Model): shirtmodel = models.CharField(_('Model of Shirt'), max_length=40) shirtclr = models.ManyToManyField(_(ShirtColorClass, verbose_name='Shirt Color')) shirtcode = models.CharField(_('Code for the shirt'), max_length=80, editable=False) #...10 more fields... def __unicode__(self): return self.shirtmodel def save(self): for item in self.shirtclr: #these are the lines I'm not sure how to do if 'Blue' in self.shirtclr: self.shirtcode = u'%s%s' % ('B', self.shirtmodel) else: self.shirtcode = self.shirtmodel super(ShirtClass,self).save() ``` At the moment I'm getting a ManyRelatedManager not Iterable message, so I know I'm doing something wrong, but I don't know what... I apologize in advance for this being a stupid newbie question. Thank you.