private function ensureStatusInstance($mixed, $strict = false)
	{
		if ( empty($mixed)) {
			if ( $strict ) {
				throw new WorkflowException('Invalid argument : null');
			} else {
				return null;
			}
		}elseif ( $mixed instanceof StatusInterface ) {
			return $mixed;
		} else {
			$status = $this->_wfSource->getStatus($mixed, $this->selectDefaultWorkflowId());
			if ( $status === null && $strict) {
				throw new WorkflowException('Status not found : '.$mixed);
			}
			return $status;
		}
	}