def get_data(users, exclude=None):
    """
    users: set of Django users
    exclude [optional]: set of Django users to exclude

    returns: {'EMAIL': u.email} for all users in users less those in `exclude`
    """
    exclude = exclude if exclude else set()
    emails = (u.email for u in users)
    return ({'EMAIL': e} for e in emails if e not in exclude)