[Minor] Cosmetic change as Model::Index is a size_t
[Minor] Cosmetic change as Model::Index is a size_t

aelkhour/pinocchio,aelkhour/pinocchio,fvalenza/pinocchio,fvalenza/pinocchio,aelkhour/pinocchio,fvalenza/pinocchio,aelkhour/pinocchio,fvalenza/pinocchio