Function ST_InteriorRingN 

pub fn ST_InteriorRingN<poly, n>(
    poly: poly,
    n: n,
) -> ST_InteriorRingN<<poly as AsExpression<Polygon>>::Expression, <n as AsExpression<Integer>>::Expression>
where
    poly: AsExpression<Polygon>,
    n: AsExpression<Integer>,

Represents the MySQL ST_ExteriorRing function