my model is :

class MyUser(db.Model):
    user = db.UserProperty()
    password = db.StringProperty(default=UNUSABLE_PASSWORD)    
    email = db.StringProperty()
    nickname = db.StringProperty(indexed=False)

and my method which want to get all username is :

s=[]
a=MyUser.all().fetch(10000)
for i in a:
    s.append(i.username)

and the error is :

AttributeError: 'MyUser' object has no attribute 'username'

so how can i get all 'username',

which is the simplest way .

thanks