add NullCheck to capabilities
add NullCheck to capabilities

benhowell/pycsw,benhowell/pycsw,kalxas/pycsw,kalxas/pycsw,kevinpdavies/pycsw,bukun/pycsw,geopython/pycsw,ckan-fcd/pycsw-fcd,ocefpaf/pycsw,rouault/pycsw,bukun/pycsw,mwengren/pycsw,tomkralidis/pycsw,PublicaMundi/pycsw,geopython/pycsw,kalxas/pycsw,ricardogsilva/pycsw,ckan-fcd/pycsw-fcd,ocefpaf/pycsw,geopython/pycsw,bukun/pycsw,tomkralidis/pycsw,mwengren/pycsw,ricardogsilva/pycsw,tomkralidis/pycsw,ricardogsilva/pycsw,ingenieroariel/pycsw,PublicaMundi/pycsw,rouault/pycsw,kevinpdavies/pycsw,ingenieroariel/pycsw