Remove redundant inheritance and imports

contracts/staking/contracts/src/Staking.sol

@@ -21,28 +21,13 @@ pragma experimental ABIEncoderV2;
 
 import "./interfaces/IStaking.sol";
 import "./sys/MixinParams.sol";
-import "./sys/MixinFinalizer.sol";
 import "./stake/MixinStake.sol";
-import "./staking_pools/MixinStakingPool.sol";
 import "./fees/MixinExchangeFees.sol";
 
 
 contract Staking is
     IStaking,
-    IStakingEvents,
-    MixinAbstract,
-    MixinConstants,
-    Ownable,
-    MixinStorage,
-    MixinExchangeManager,
-    MixinScheduler,
     MixinParams,
-    MixinStakeStorage,
-    MixinStakeBalances,
-    MixinCumulativeRewards,
-    MixinStakingPoolRewards,
-    MixinFinalizer,
-    MixinStakingPool,
     MixinStake,
     MixinExchangeFees
 {

contracts/staking/contracts/src/StakingProxy.sol

@@ -27,8 +27,6 @@ import "./interfaces/IStakingProxy.sol";
 
 contract StakingProxy is
     IStakingProxy,
-    MixinConstants,
-    Ownable,
     MixinStorage
 {
     using LibProxy for address;

contracts/staking/contracts/src/fees/MixinExchangeFees.sol

@@ -19,33 +19,20 @@
 pragma solidity ^0.5.9;
 pragma experimental ABIEncoderV2;
 
-import "@0x/contracts-erc20/contracts/src/interfaces/IEtherToken.sol";
 import "@0x/contracts-exchange-libs/contracts/src/LibMath.sol";
 import "@0x/contracts-utils/contracts/src/LibRichErrors.sol";
 import "@0x/contracts-utils/contracts/src/LibSafeMath.sol";
 import "../libs/LibStakingRichErrors.sol";
-import "../libs/LibCobbDouglas.sol";
 import "../interfaces/IStructs.sol";
-import "../stake/MixinStakeBalances.sol";
 import "../sys/MixinFinalizer.sol";
 import "../staking_pools/MixinStakingPool.sol";
 import "./MixinExchangeManager.sol";
 
 
 contract MixinExchangeFees is
-    IStakingEvents,
-    MixinAbstract,
-    MixinConstants,
-    Ownable,
-    MixinStorage,
     MixinExchangeManager,
-    MixinScheduler,
+    MixinStakingPool,
-    MixinStakeStorage,
+    MixinFinalizer
-    MixinStakeBalances,
-    MixinCumulativeRewards,
-    MixinStakingPoolRewards,
-    MixinFinalizer,
-    MixinStakingPool
 {
     using LibSafeMath for uint256;
 

contracts/staking/contracts/src/fees/MixinExchangeManager.sol

@@ -30,8 +30,6 @@ import "../immutable/MixinStorage.sol";
 /// then it should be removed.
 contract MixinExchangeManager is
     IStakingEvents,
-    MixinConstants,
-    Ownable,
     MixinStorage
 {
     /// @dev Asserts that the call is coming from a valid exchange.

contracts/staking/contracts/src/stake/MixinStake.sol

@@ -20,23 +20,12 @@ pragma solidity ^0.5.9;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-utils/contracts/src/LibSafeMath.sol";
-import "../staking_pools/MixinStakingPoolRewards.sol";
 import "../staking_pools/MixinStakingPool.sol";
 import "../libs/LibStakingRichErrors.sol";
 
 
 /// @dev This mixin contains logic for managing ZRX tokens and Stake.
 contract MixinStake is
-    IStakingEvents,
-    MixinAbstract,
-    MixinConstants,
-    Ownable,
-    MixinStorage,
-    MixinScheduler,
-    MixinStakeStorage,
-    MixinStakeBalances,
-    MixinCumulativeRewards,
-    MixinStakingPoolRewards,
     MixinStakingPool
 {
     using LibSafeMath for uint256;

contracts/staking/contracts/src/stake/MixinStakeBalances.sol

@@ -27,11 +27,6 @@ import "./MixinStakeStorage.sol";
 /// @dev This mixin contains logic for querying stake balances.
 /// **** Read MixinStake before continuing ****
 contract MixinStakeBalances is
-    IStakingEvents,
-    MixinConstants,
-    Ownable,
-    MixinStorage,
-    MixinScheduler,
     MixinStakeStorage
 {
     using LibSafeMath for uint256;

contracts/staking/contracts/src/stake/MixinStakeStorage.sol

@@ -26,10 +26,6 @@ import "../sys/MixinScheduler.sol";
 
 /// @dev This mixin contains logic for managing stake storage.
 contract MixinStakeStorage is
-    IStakingEvents,
-    MixinConstants,
-    Ownable,
-    MixinStorage,
     MixinScheduler
 {
     using LibSafeMath for uint256;

contracts/staking/contracts/src/staking_pools/MixinCumulativeRewards.sol

@@ -25,12 +25,6 @@ import "../stake/MixinStakeBalances.sol";
 
 
 contract MixinCumulativeRewards is
-    IStakingEvents,
-    MixinConstants,
-    Ownable,
-    MixinStorage,
-    MixinScheduler,
-    MixinStakeStorage,
     MixinStakeBalances
 {
     using LibSafeMath for uint256;

contracts/staking/contracts/src/staking_pools/MixinStakingPool.sol

@@ -23,19 +23,12 @@ import "@0x/contracts-utils/contracts/src/LibRichErrors.sol";
 import "@0x/contracts-utils/contracts/src/LibSafeMath.sol";
 import "../libs/LibStakingRichErrors.sol";
 import "../interfaces/IStructs.sol";
+import "../sys/MixinAbstract.sol";
 import "./MixinStakingPoolRewards.sol";
 
 
 contract MixinStakingPool is
-    IStakingEvents,
     MixinAbstract,
-    MixinConstants,
-    Ownable,
-    MixinStorage,
-    MixinScheduler,
-    MixinStakeStorage,
-    MixinStakeBalances,
-    MixinCumulativeRewards,
     MixinStakingPoolRewards
 {
     using LibSafeMath for uint256;

contracts/staking/contracts/src/staking_pools/MixinStakingPoolRewards.sol

@@ -27,14 +27,7 @@ import "../sys/MixinAbstract.sol";
 
 
 contract MixinStakingPoolRewards is
-    IStakingEvents,
     MixinAbstract,
-    MixinConstants,
-    Ownable,
-    MixinStorage,
-    MixinScheduler,
-    MixinStakeStorage,
-    MixinStakeBalances,
     MixinCumulativeRewards
 {
     using LibSafeMath for uint256;

contracts/staking/contracts/src/sys/MixinAbstract.sol

@@ -19,8 +19,6 @@
 pragma solidity ^0.5.9;
 pragma experimental ABIEncoderV2;
 
-import "../interfaces/IStructs.sol";
-
 
 /// @dev Exposes some internal functions from various contracts to avoid
 ///      cyclical dependencies.

contracts/staking/contracts/src/sys/MixinFinalizer.sol

@@ -19,18 +19,12 @@
 pragma solidity ^0.5.9;
 pragma experimental ABIEncoderV2;
 
-import "@0x/contracts-erc20/contracts/src/interfaces/IEtherToken.sol";
 import "@0x/contracts-utils/contracts/src/LibRichErrors.sol";
 import "@0x/contracts-utils/contracts/src/LibSafeMath.sol";
 import "../libs/LibCobbDouglas.sol";
 import "../libs/LibStakingRichErrors.sol";
-import "../immutable/MixinStorage.sol";
-import "../immutable/MixinConstants.sol";
-import "../interfaces/IStakingEvents.sol";
 import "../interfaces/IStructs.sol";
-import "../stake/MixinStakeBalances.sol";
+import "../staking_pools/MixinStakingPoolRewards.sol";
-import "../staking_pools/MixinStakingPool.sol";
-import "./MixinScheduler.sol";
 
 
 /// @dev This mixin contains functions related to finalizing epochs.
@@ -39,15 +33,6 @@ import "./MixinScheduler.sol";
 ///      the contract from stalling while we finalize rewards for the previous
 ///      epoch.
 contract MixinFinalizer is
-    IStakingEvents,
-    MixinAbstract,
-    MixinConstants,
-    Ownable,
-    MixinStorage,
-    MixinScheduler,
-    MixinStakeStorage,
-    MixinStakeBalances,
-    MixinCumulativeRewards,
     MixinStakingPoolRewards
 {
     using LibSafeMath for uint256;

contracts/staking/contracts/src/sys/MixinParams.sol

@@ -26,8 +26,6 @@ import "../libs/LibStakingRichErrors.sol";
 
 contract MixinParams is
     IStakingEvents,
-    MixinConstants,
-    Ownable,
     MixinStorage
 {
     /// @dev Set all configurable parameters at once.

contracts/staking/contracts/src/sys/MixinScheduler.sol

@@ -33,8 +33,6 @@ import "../interfaces/IStakingEvents.sol";
 /// and consistent scheduling metric than time. TimeLocks, for example, are measured in epochs.
 contract MixinScheduler is
     IStakingEvents,
-    MixinConstants,
-    Ownable,
     MixinStorage
 {
     using LibSafeMath for uint256;

contracts/staking/contracts/src/vaults/ZrxVault.sol

@@ -34,7 +34,6 @@ import "./MixinVaultCore.sol";
 /// failure mode, it cannot be returned to normal mode; this prevents
 /// corruption of related state in the staking contract.
 contract ZrxVault is
-    IVaultCore,
     IZrxVault,
     MixinVaultCore
 {