Inject index properly into ReferendumInfo (with unwrap) (#718)

* Inject inject properly into ReferendumInfo (with unwrap)

* Use unwrapOr

* Fix type import

packages/types/src/type/ReferendumInfo.ts

@@ -2,8 +2,10 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
-import BlockNumber from './BlockNumber';
+import { Codec } from '../types';
+
 import Struct from '../codec/Struct';
+import BlockNumber from './BlockNumber';
 import Proposal from './Proposal';
 import VoteThreshold from './VoteThreshold';
 
@@ -20,7 +22,7 @@ type ReferendumInfoValue = {
  * Info regarding an ongoing referendum
  */
 export default class ReferendumInfo extends Struct {
-  constructor (value?: ReferendumInfoValue | Uint8Array) {
+  constructor (value?: ReferendumInfoValue | Uint8Array | Map<string, Codec>) {
     super({
       end: BlockNumber,
       proposal: Proposal,