def update_email_to_lower(apps, schema_editor):
User = apps.get_model('userprofile', 'User')
conflicts = 0

for user_update in User.objects.all():
    email = user_update.email
    if User.objects.filter(email__iexact=email).count() == 1:
        user_update.email = email.lower()
        user_update.save()
    else:
        conflicts += 1
print conflicts

AttributeError: 'User' object has no attribute 'get_full_name'

def get_full_name(self):
    """Returns the full name for a user
    """
    if self.first_name and self.last_name:
        return u'{0} {1}'.format(
            self.first_name.strip(),
            self.last_name.strip()
        ).title()

    elif self.first_name:
        return u'{0}'.format(self.first_name.strip()).title()

    elif self.last_name:
        return u'{0}'.format(self.last_name.strip()).title()

    else:
        return self.email.split('@')[0].lower()

class UserManager(BaseUserManager):
use_in_migrations = True
    def create_user(self, email, password=None, is_active=True):
      .
      .
      .