I met this problem (Django base.py: 'str' object is not callable) when I go through a Django tutorial:

photo/models.py:
Code:
from django.db import models
from django.contrib.auth.models import User
from django.contrib import admin

class Album(models.Model):
    title = models.CharField(max_length=60)
    public = models.BooleanField(default=False)
    def __unicode__(self):
...