How to use the stellar-base.xdr.Memo function in stellar-base

})(function (id) {
                if (Number(id) === "NaN") {
                    throw new Error("Expects a int64 as a string. Got " + id);
                }
                return xdr.Memo.memoId(id);
            })
        },

value: function none() {
                return xdr.Memo.memoNone();
            }
        },

static hash(hash) {
        if (typeof hash === "string" && Buffer.byteLength(hash) != 32) {
            throw new Error("Expects a 32 byte hash value. Got " + Buffer.byteLength(hash) + " bytes instead");
        }
        return xdr.Memo.memoHash(hash);
    }