如何在Django admin

Question

我想获得所选的外键值。 这是我的model.py

models.py

class EmailList(models.Model):
    email = models.EmailField(unique=True)
    full_name = models.CharField(max_length=120, blank=True, null=True)

    def __unicode__(self):
        return self.email

class SendEmail(models.Model):
    select_email = models.ForeignKey(EmailList)

    def __unicode__(self):
        return self.select_email.email

admin.py

class SendEmailAdmin(admin.ModelAdmin):
    change_form_template = "admin/newsletter/SendEmail/change_form.html"
    form = SendEmailForm
    def get_form(self, request, obj=None, **kwargs):
        if request.method == 'POST':
            form = SendEmailForm(request.POST)
            if form.is_valid():

                # *** Here I want to get selected Foreign key value *** 

                subject = form.cleaned_data['subject']
                message = form.cleaned_data['message']
                return SendEmailForm
        return SendEmailForm    

在此代码中我尝试向特定用户发送电子邮件，但我不明白如何获取所选的外键值..plz帮助我。