message: updating to get prev block balance for SDK Assets.getNativeTokenBalance
diff: import ERC20ABI from '../contracts/abi/erc-20';
  import { AbiItem } from 'web3-utils';
  import Web3 from 'web3';
  -import { safeContractCall } from './utils/general-utils';
  +import { networkName, safeContractCall } from './utils/general-utils';
  export interface IAssets {
  getNativeTokenBalance(userAddress?: string): Promise<string>;
  @@ -15,6 +15,10 @@ export default class Assets implements IAssets {
  async getNativeTokenBalance(userAddress?: string): Promise<string> {
  let address = userAddress ?? (await this.web3.eth.getAccounts())[0];
  + if (['kovan', 'mainnet'].includes(await networkName(this.web3))) {
  + let previousBlockNumber = (await this.web3.eth.getBlockNumber()) - 1;
  + return this.web3.eth.getBalance(address, previousBlockNumber);
  + }
  return this.web3.eth.getBalance(address);
  }
  