Function sweep_profile_twisted_anchored 

pub fn sweep_profile_twisted_anchored(
    profile: &[NurbsCurve],
    path: &NurbsCurve,
    twist_angle: f64,
    name: Option<&str>,
    anchor: ProfileAnchor,
) -> Result<BrepSolid, String>

sweep_profile_twisted with an explicit placement anchor: the hole loop twists about the SAME path axis as its outer loop (shared anchor), so the cutter stays registered with the outer wall through the whole twist.