public static Either <Left, CollTo> mapRightC <CollFrom, CollTo, Left, ElemFrom, ElemTo>(
this Either <Left, CollFrom> e,
Fn <ElemFrom, ElemTo> mapper,
Fn <IEnumerable <ElemTo>, CollTo> toCollection
)
where CollFrom : IEnumerable <ElemFrom>
where CollTo : IEnumerable <ElemTo>
=> e.mapRightC(mapper).mapRight(toCollection);