'Mark that this attempt could not be completed because of a system error.
Status should be moved to `must_retry`. For example, if Software Secure
reported to us that they couldn\'t process our submission because they
couldn\'t decrypt the image we sent.'

@status_before_must_be('must_retry', 'submitted', 'approved', 'denied')
def system_error(self, error_msg, error_code='', reviewing_user=None, reviewing_service=''):

    if (self.status in ['approved', 'denied']):
        return
    self.error_msg = error_msg
    self.error_code = error_code
    self.reviewing_user = reviewing_user
    self.reviewing_service = reviewing_service
    self.status = 'must_retry'
    self.save()
