Function _burnToken(address from,uint256 tokenId_,uint256 amount_) internal

INTERNAL FUNCTION

1. Intended behavior.

   • The internal function, which allows burning amount_ of Bond tokenId_ tokens from from address and decreases supply value for this tokenId_.

2. Negative behavior.

   • users should not have unrestricted access to this function. The caller function should control from parameter, not allowing users to burn other user's tokens.

   • shouldn’t allow burning tokens if the user does not have enough tokens, partial burn should be impossible. should reject in this case

3. Preconditions.

   • user fromshould have ≥ amount of tokenId_ tokens.

   • the caller function should not allow to user pass any from address.

4. Postconditions.

   • the supply pf the bondToken should decrease by amount

   • the balance of the user in terms of bondTokens should decrease by amount.

5. Inputs.

6. Examine all function calls the function makes.

   a. Call to burn(from, tokenId_, amount_)

   • What is controllable? (callee, params, return value): the calling function should not allow the user to control the from value

   • If return value controllable, how is it used and how can it go wrong? there is no return value

   • What happens if it reverts or tries to reenter? N/A