Why could not add this insertCutSurface feature ?

Hi Guys,

Why could not add this insertCutSurface feature ? as the below picture shows, the macro has already select a plane, then why the  insertCutSurface showed the errors=0 , means no error , but cut no solid ?

swSurfaceCutFeatureError_BodiesNotSpecified1 = No bodies specified to cut
swSurfaceCutFeatureError_InvalidVariant2 = Array passed to IFeatureManager::InsertCutSurface must contain only body objects
swSurfaceCutFeatureError_NoError

0 = No error

SolidworksApi macros