Fix lintr error
Fix lintr error

daniel0128/receptormarker,daniel0128/receptormarker,catterbu/receptormarker,catterbu/receptormarker,nsh87/receptormarker,nsh87/receptormarker,nsh87/receptormarker,catterbu/receptormarker,catterbu/receptormarker,daniel0128/receptormarker,catterbu/receptormarker,daniel0128/receptormarker,daniel0128/receptormarker,daniel0128/receptormarker,daniel0128/receptormarker,nsh87/receptormarker,nsh87/receptormarker