message: fetch balance
diff: @@ -46,6 +46,30 @@ export default class Matic extends ContractsBase {
  this.web3Client.wallet = _wallet
  }
  + async balanceOfERC20(userAddress: address, token: address, options?: SendOptions) {
  + if (options && (!token || !userAddress)) {
  + throw new Error('token address or user address is missing')
  + }
  +
  + const balance = this.getERC20TokenContract(
  + 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')
  + }
  +
  + const tokenID = this.getERC721TokenContract(
  + token,
  + options.parent,
  + ).methods.tokenOfOwnerByIndex(userAddress, index).call()
  + return tokenID
  + }
  +
  async transferERC20Tokens(
  token: address,
  to: address,
  