<snip>

    if address not in builder.accounts:

        builder.accounts[address] = AccountData()

    <snip>

    ensure_account(builder, address)

    if slot not in builder.accounts[address].storage_changes:

        builder.accounts[address].storage_changes[slot] = []

    # Check if there's already an entry with the same block_access_index

    # If so, update it with the new value, keeping only the final write

    changes = builder.accounts[address].storage_changes[slot]

    for i, existing_change in enumerate(changes):

        if existing_change.block_access_index == block_access_index:

            # Update the existing entry with the new value

            changes[i] = StorageChange(

                block_access_index=block_access_index, new_value=new_value

            )

            return

    # No existing entry found, append new change

    change = StorageChange(

        block_access_index=block_access_index, new_value=new_value

    )

    builder.accounts[address].storage_changes[slot].append(change)

    <snip>

    ensure_account(builder, address)

    builder.accounts[address].storage_reads.add(slot)

    <snip>

    ensure_account(builder, address)

    # Balance value is already U256

    balance_value = post_balance

    # Check if we already have a balance change for this tx_index and update it

    # This ensures we only track the final balance per transaction

    existing_changes = builder.accounts[address].balance_changes

    for i, existing in enumerate(existing_changes):

        if existing.block_access_index == block_access_index:

            # Update the existing balance change with the new balance

            existing_changes[i] = BalanceChange(

                block_access_index=block_access_index,

                post_balance=balance_value,

            )

            return

    # No existing change for this tx_index, add a new one

    change = BalanceChange(

        block_access_index=block_access_index, post_balance=balance_value

    )

    builder.accounts[address].balance_changes.append(change)

    <snip>

    ensure_account(builder, address)

    # Check if we already have a nonce change for this tx_index and update it

    # This ensures we only track the final (highest) nonce per transaction

    existing_changes = builder.accounts[address].nonce_changes

    for i, existing in enumerate(existing_changes):

        if existing.block_access_index == block_access_index:

            # Keep the highest nonce value

            if new_nonce > existing.new_nonce:

                existing_changes[i] = NonceChange(

                    block_access_index=block_access_index, new_nonce=new_nonce

                )

            return

    # No existing change for this tx_index, add a new one

    change = NonceChange(

        block_access_index=block_access_index, new_nonce=new_nonce

    )

    builder.accounts[address].nonce_changes.append(change)

    <snip>

    ensure_account(builder, address)

    # Check if we already have a code change for this block_access_index

    # This handles the case of in-transaction selfdestructs where code is

    # first deployed and then cleared in the same transaction

    existing_changes = builder.accounts[address].code_changes

    for i, existing in enumerate(existing_changes):

        if existing.block_access_index == block_access_index:

            # Replace the existing code change with the new one

            # For selfdestructs, this ensures we only record the final

            # state (empty code)

            existing_changes[i] = CodeChange(

                block_access_index=block_access_index, new_code=new_code

            )

            return

    # No existing change for this block_access_index, add a new one

    change = CodeChange(

        block_access_index=block_access_index, new_code=new_code

    )

    builder.accounts[address].code_changes.append(change)

    <snip>

    if address not in builder.accounts:

        return

    storage_changes = builder.accounts[address].storage_changes

    if slot not in storage_changes:

        return

    storage_changes[slot] = [

        change

        for change in storage_changes[slot]

        if change.block_access_index != block_access_index

    ]

    if not storage_changes[slot]:

        del storage_changes[slot]

    <snip>

    if address not in builder.accounts:

        return

    account = builder.accounts[address]

    account.balance_changes = [

        change

        for change in account.balance_changes

        if change.block_access_index != block_access_index

    ]

    <snip>

    if address not in builder.accounts:

        return

    account = builder.accounts[address]

    account.nonce_changes = [

        change

        for change in account.nonce_changes

        if change.block_access_index != block_access_index

    ]

    <snip>

    if address not in builder.accounts:

        return

    account = builder.accounts[address]

    account.code_changes = [

        change

        for change in account.code_changes

        if change.block_access_index != block_access_index

    ]

    <snip>  # noqa: E501

    ensure_account(builder, address)

    <snip>  # noqa: E501

    block_access_list: BlockAccessList = []

    for address, changes in builder.accounts.items():

        storage_changes = []

        for slot, slot_changes in changes.storage_changes.items():

            sorted_changes = tuple(

                sorted(slot_changes, key=lambda x: x.block_access_index)

            )

            storage_changes.append(

                SlotChanges(slot=slot, changes=sorted_changes)

            )

        storage_reads = []

        for slot in changes.storage_reads:

            if slot not in changes.storage_changes:

                storage_reads.append(slot)

        balance_changes = tuple(

            sorted(changes.balance_changes, key=lambda x: x.block_access_index)

        )

        nonce_changes = tuple(

            sorted(changes.nonce_changes, key=lambda x: x.block_access_index)

        )

        code_changes = tuple(

            sorted(changes.code_changes, key=lambda x: x.block_access_index)

        )

        storage_changes.sort(key=lambda x: x.slot)

        storage_reads.sort()

        account_change = AccountChanges(

            address=address,

            storage_changes=tuple(storage_changes),

            storage_reads=tuple(storage_reads),

            balance_changes=balance_changes,

            nonce_changes=nonce_changes,

            code_changes=code_changes,

        )

        block_access_list.append(account_change)

    block_access_list.sort(key=lambda x: x.address)

    return block_access_list

    <snip>

    if address in pre_tx_accounts:

        return pre_tx_accounts[address]

    return pre_state.get_account_optional(address)

    <snip>

    if address in block_state.storage_writes:

        if key in block_state.storage_writes[address]:

            return block_state.storage_writes[address][key]

    if address in block_state.storage_clears:

        return U256(0)

    return block_state.pre_state.get_storage(address, key)

    <snip>

    key = (builder.block_access_index, address)

    if key not in builder.index_start_accounts:

        builder.index_start_accounts[key] = _get_pre_tx_account(

            block_state.account_writes, block_state.pre_state, address

        )

    return builder.index_start_accounts[key]

    <snip>

    index_key = (builder.block_access_index, address, key)

    if index_key not in builder.index_start_storage:

        builder.index_start_storage[index_key] = _get_pre_tx_storage(

            block_state, address, key

        )

    return builder.index_start_storage[index_key]

    <snip>

    block_state = tx_state.parent

    idx = builder.block_access_index

    for address, post_account in tx_state.account_writes.items():

        pre_account = _index_start_account(builder, block_state, address)

        pre_balance = pre_account.balance if pre_account else U256(0)

        post_balance = post_account.balance if post_account else U256(0)

        if pre_balance != post_balance:

            add_balance_change(builder, address, idx, post_balance)

        else:

            remove_balance_change(builder, address, idx)

        pre_nonce = pre_account.nonce if pre_account else Uint(0)

        post_nonce = post_account.nonce if post_account else Uint(0)

        if pre_nonce != post_nonce:

            add_nonce_change(builder, address, idx, U64(post_nonce))

        else:

            remove_nonce_change(builder, address, idx)

        pre_code_hash = (

            pre_account.code_hash if pre_account else EMPTY_CODE_HASH

        )

        post_code_hash = (

            post_account.code_hash if post_account else EMPTY_CODE_HASH

        )

        if pre_code_hash != post_code_hash:

            post_code = get_code(tx_state, post_code_hash)

            add_code_change(builder, address, idx, post_code)

        else:

            remove_code_change(builder, address, idx)

    for address, slots in tx_state.storage_writes.items():

        for key, post_value in slots.items():

            pre_value = _index_start_storage(

                builder, block_state, address, key

            )

            # Convert slot from internal Bytes32 format to U256 for BAL.

            # EIP-7928 uses U256 as it's more space-efficient in RLP.

            u256_slot = U256.from_be_bytes(key)

            if pre_value != post_value:

                add_storage_write(builder, address, u256_slot, idx, post_value)

            else:

                remove_storage_write(builder, address, u256_slot, idx)

    <snip>  # noqa: E501

    # Add storage reads (convert Bytes32 to U256 for BAL encoding)

    for address, slot in block_state.storage_reads:

        add_storage_read(builder, address, U256.from_be_bytes(slot))

    # Add touched addresses

    for address in block_state.account_reads:

        add_touched_account(builder, address)

    return _build_from_builder(builder)

    <snip>

    return keccak256(rlp.encode(block_access_list))

    <snip>

    from .vm.gas import GasCosts

    bal_items = Uint(0)

    for account in block_access_list:

        # Count each address as one item

        bal_items += Uint(1)

        # Collect unique storage keys across both

        # reads and writes

        unique_slots: Set[U256] = set()

        for slot_change in account.storage_changes:

            unique_slots.add(slot_change.slot)

        for slot in account.storage_reads:

            unique_slots.add(slot)

        # Count each unique storage key as one item

        bal_items += ulen(unique_slots)

    if bal_items > block_gas_limit // GasCosts.BLOCK_ACCESS_LIST_ITEM:

        raise BlockAccessListGasLimitExceededError(

            f"Block access list exceeds gas limit, {bal_items} items "

            f"exceeds limit of "

            f"{block_gas_limit // GasCosts.BLOCK_ACCESS_LIST_ITEM}."

        )