Function interp_hashset_diff 

fn interp_hashset_diff(
    args: &[RValue],
    named: &[(String, RValue)],
    context: &BuiltinContext<'_>,
) -> Result<RValue, RError>

Compute the difference of two HashSets (s1 minus s2), returning a new HashSet.

@param s1 integer scalar: first hashset ID @param s2 integer scalar: second hashset ID @return integer scalar with class “hashset”: elements in s1 but not in s2