message: fetch balance of ERC721
diff: @@ -58,6 +58,18 @@ export default class Matic extends ContractsBase {
  return balance
  }
  + async balanceOfERC721(userAddress: address, token: address, options?: SendOptions) {
  + if (options && (!token || !userAddress)) {
  + throw new Error('token address or user address is missing')
  + }
  +
  + const balance = this.getERC721TokenContract(
  + token,
  + options.parent,
  + ).methods.balanceOf(userAddress).call()
  + return balance
  + }
  +
  async tokenOfOwnerByIndexERC721(userAddress: address, token: address, index: number, options?: SendOptions) {
  if (options && (!token || !userAddress)) {
  throw new Error('token address or user address is missing')
  