BalancerLBPSwapper - tokenSpent and tokenReceived should be immutable
Acc. to the inline comment both `tokenSpent` and `tokenReceived` should be immutable but they are not declared as such.\\n```\\n// tokenSpent and tokenReceived are immutable\\ntokenSpent = \\_tokenSpent;\\ntokenReceived = \\_tokenReceived;\\n```\\n\\n```\\n/// @notice the token to be auctioned\\naddress public override tokenSpent;\\n\\n/// @notice the token to buy\\naddress public override tokenReceived;\\n```\\n
Declare both variable `immutable`.
```\\n// tokenSpent and tokenReceived are immutable\\ntokenSpent = \\_tokenSpent;\\ntokenReceived = \\_tokenReceived;\\n```\\n