Confirms the specified user

    :param user: The user to confirm

def confirm_user(user):
    """Confirms the specified user

    :param user: The user to confirm
    """
    if user.confirmed_at is not None:
        return False
    user.confirmed_at = _security.datetime_factory()
    _datastore.put(user)
    user_confirmed.send(app._get_current_object(), user=user)
    return True