code: def _add_transaction_to_canonical_chain(db: BaseDB,
                                              transaction_hash: Hash32,
                                              block_header: BlockHeader,
                                              index: int) -> None:
          
          transaction_key = TransactionKey(block_header.block_number, index)
          db.set(
              SchemaV1.make_transaction_hash_to_block_lookup_key(transaction_hash),
              rlp.encode(transaction_key),
          )
docs: :param bytes transaction_hash: the hash of the transaction to add the lookup for
          :param block_header: The header of the block with the txn that is in the canonical chain
          :param int index: the position of the transaction in the block
          - add lookup from transaction hash to the block number and index that the body is stored at
          - remove transaction hash to body lookup in the pending pool