1 files changed, 5 insertions, 6 deletions
diff --git a/packages/contract-wrappers/src/contract_wrappers/ether_token_wrapper.ts b/packages/contract-wrappers/src/contract_wrappers/ether_token_wrapper.ts
index d4a08da86..913c47cf7 100644
--- a/packages/contract-wrappers/src/contract_wrappers/ether_token_wrapper.ts
+++ b/packages/contract-wrappers/src/contract_wrappers/ether_token_wrapper.ts
@@ -8,22 +8,21 @@ import * as _ from 'lodash';
 
 import { BlockRange, ContractWrappersError, EventCallback, IndexedFilterValues, TransactionOpts } from '../types';
 import { assert } from '../utils/assert';
+import { utils } from '../utils/utils';
 
 import { ContractWrapper } from './contract_wrapper';
 import { ERC20TokenWrapper } from './erc20_token_wrapper';
 
-const removeUndefinedProperties = _.pickBy;
-
 /**
  * This class includes all the functionality related to interacting with a wrapped Ether ERC20 token contract.
  * The caller can convert ETH into the equivalent number of wrapped ETH ERC20 tokens and back.
  */
 export class EtherTokenWrapper extends ContractWrapper {
     public abi: ContractAbi = WETH9.compilerOutput.abi;
-    private _etherTokenContractsByAddress: {
+    private readonly _etherTokenContractsByAddress: {
         [address: string]: WETH9Contract;
     } = {};
-    private _erc20TokenWrapper: ERC20TokenWrapper;
+    private readonly _erc20TokenWrapper: ERC20TokenWrapper;
     /**
      * Instantiate EtherTokenWrapper.
      * @param web3Wrapper Web3Wrapper instance to use
@@ -67,7 +66,7 @@ export class EtherTokenWrapper extends ContractWrapper {
 
         const wethContract = await this._getEtherTokenContractAsync(normalizedEtherTokenAddress);
         const txHash = await wethContract.deposit.sendTransactionAsync(
-            removeUndefinedProperties({
+            utils.removeUndefinedProperties({
                 from: normalizedDepositorAddress,
                 value: amountInWei,
                 gas: txOpts.gasLimit,
@@ -109,7 +108,7 @@ export class EtherTokenWrapper extends ContractWrapper {
         const wethContract = await this._getEtherTokenContractAsync(normalizedEtherTokenAddress);
         const txHash = await wethContract.withdraw.sendTransactionAsync(
             amountInWei,
-            removeUndefinedProperties({
+            utils.removeUndefinedProperties({
                 from: normalizedWithdrawerAddress,
                 gas: txOpts.gasLimit,
                 gasPrice: txOpts.gasPrice,