How to use the monocle-ts.Prism.fromPredicate function in monocle-ts

export function _right(): Prism, These> { return Prism.fromPredicate(s => s.type === "Right"); }

export const bar: FooBar = { type: "Bar" };

export function fold(fa: FooBar, onFoo: R, onBar: R): R { switch (fa.type) {
    case "Foo": return onFoo;
    case "Bar": return onBar;
} }

export function foldL(fa: FooBar, onFoo: () => R, onBar: () => R): R { switch (fa.type) {
    case "Foo": return onFoo();
    case "Bar": return onBar();
} }

import { Prism } from "monocle-ts";

export const _Foo: Prism = Prism.fromPredicate(s => s.type === "Foo");

export const _Bar: Prism = Prism.fromPredicate(s => s.type === "Bar");

export function _right(): Prism, Either> { return Prism.fromPredicate(s => s.type === "Right"); }

export function _just<a>(): Prism, Maybe</a><a>&gt; { return Prism.fromPredicate(s =&gt; s.type === "Just"); }
</a>

export function _fetching<a>(): Prism, Constrained</a><a>&gt; { return Prism.fromPredicate(s =&gt; s.type === "Fetching"); }
</a>

export const createRangePrism = (from: number, to: number): Prism => {
  return Prism.fromPredicate(n => n >= from && n <= to)
}

export function _nothing<a>(): Prism, Maybe</a><a>&gt; { return Prism.fromPredicate(s =&gt; s.type === "Nothing"); }
</a>

export function _left(): Prism, Either> { return Prism.fromPredicate(s => s.type === "Left"); }

export function _leaf<a>(): Prism, Tree</a><a>&gt; { return Prism.fromPredicate(s =&gt; s.type === "Leaf"); }
</a>

export function _none<a>(): Prism, Option</a><a>&gt; { return Prism.fromPredicate(s =&gt; s.type === "None"); }
</a>