+ if ( sourceVertex1.IsNull() != sourceVertex2.IsNull() )
+ {
+ // possibly there is only 1 vertex in the face
+ if ( !_sourceFace.IsNull() &&
+ SMESH_MesherHelper::Count( _sourceFace, TopAbs_VERTEX, /*ignoreSame=*/true) != 1 )
+ throw SALOME_Exception(LOCALIZED("Two or none pairs of vertices must be provided"));
+ }
+
+ if ( !sourceVertex1.IsNull() )