How to lookup django session for a particular user?

from django.contrib.sessions.models import Session
from django.contrib.auth.models import User

session_key = '8cae76c505f15432b48c8292a7dd0e54'

session = Session.objects.get(session_key=session_key)
uid = session.get_decoded().get('_auth_user_id')
user = User.objects.get(pk=uid)

print user.username, user.get_full_name(), user.email

class Session(models.Model):

    ...

    user_id = models.IntegerField(_('user_id'), null=True)

    ...

    def save(self, *args, **kwargs):
        user_id = self.get_decoded().get('_auth_user_id')
        if ( user_id != None ):
            self.user_id = user_id

        # Call the "real" save() method.
        super(Session, self).save(*args, **kwargs)

# On login, destroy all prev sessions
        # This disallows multiple logins from different browsers
        dbSessions = Session.objects.filter( user_id = request.user.id )
        for index, dbSession in enumerate( dbSessions ):
            if ( dbSession.session_key != request.session.session_key ):
                dbSession.delete()