Function: burn(uint256 amount)
This function burns the asset token.
Inputs
amountControl: Fully controlled by the caller of AssetIssuer.
Constraints: Must be less than the balance of the caller.
Impact: Specifies the amount of asset tokens to burn.
Branches and code coverage
Intended branches
Burn the asset token.
Change the basket.
Negative behavior
The caller is an issuer.