Body

function(o,k,func){
  try {
    if (k in o){
      if (func !== undefined){
        return Some(func(o[k]));
      } else {
        return Some(o[k]);
      }
    } else {
      return None;
    }
  } catch (ex){
    error('exception in optionally',o,k,ex);
    return None;
  }
}