private boolean outsideBlockchainRange(final long blockNumber) {
    return blockNumber > headBlockNumber() || blockNumber < BlockHeader.GENESIS_BLOCK_NUMBER;
  }
Calculate and return the value of the base fee for the next block, if the network has a base
fee market, otherwise return empty.

@return the optional base fee
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/query/BlockchainQueries.java