def create(self, created_by, subject, body, recipients=None,

               type_=Notification.TYPE_MESSAGE, with_email=True,

               email_kwargs=None, repo_name=None):

        """

        Creates notification of given type

        :param created_by: int, str or User instance. User who created this

            notification

        :param subject:

        :param body:

        :param recipients: list of int, str or User objects, when None

            is given send to all admins

        :param type_: type of notification

        :param with_email: send email with this notification

        :param email_kwargs: additional dict to pass as args to email template

        """

        from kallithea.lib.celerylib import tasks

        email_kwargs = email_kwargs or {}

        if recipients and not getattr(recipients, '__iter__', False):

            raise Exception('recipients must be a list or iterable')

        created_by_obj = User.guess_instance(created_by)

        if recipients:

            for u in recipients:

                obj = User.guess_instance(u)

                if obj is not None:

                else:

                    # TODO: inform user that requested operation couldn't be completed

                    log.error('cannot email unknown user %r', u)

            log.debug('sending notifications %s to %s',

                type_, recipients_objs

            )

        elif recipients is None:

            # empty recipients means to all admins

            recipients_objs = User.query().filter(User.admin == True).all()

            log.debug('sending notifications %s to admins: %s',

                type_, recipients_objs

            )

        #else: silently skip notification mails?

        # TODO: inform user who are notified

        notif = Notification.create(

            created_by=created_by_obj, subject=subject,

            body=body, recipients=recipients_objs, type_=type_

        )

        if not with_email:

            return notif

        headers = {}

        headers['X-Kallithea-Notification-Type'] = type_

        if 'threading' in email_kwargs:

            headers['References'] = ' '.join('<%s>' % x for x in email_kwargs['threading'])