':return: All usernames collected by other plugins and from DBs'

def _get_users(self):

    for tag in {OS, APPLICATION}:
        for (user_desc, user) in get_users_from_csv(tag):
            (yield (user_desc, user, tag))
    for user in self.COMMON_USERS:
        (yield (self.COMMON_USER_DESC, user, self.COMMON_TAG))
    for email_kb in kb.kb.get('emails', 'emails'):
        (yield (self.EMAIL_USER_DESC, email_kb['user'], self.EMAIL_TAG))
