Python social auth why can't get email?

Question

Django

I am using python social auth for Django. I signed up with facebook. The first and last names go into the User model, but the email doesn't appear there. Why?
Here is my settings.py:

SOCIAL_AUTH_FACEBOOK_KEY = 'xxx'
SOCIAL_AUTH_FACEBOOK_SECRET = 'xxx'
SOCIAL_AUTH_FACEBOOK_SCOPE = ['email']
SOCIAL_AUTH_USERNAME_IS_FULL_EMAIL = True
SOCIAL_AUTH_FACEBOOK_PROFILE_EXTRA_PARAMS = {
    'fields': 'id, name, email'
}