@Override
            public void disposeTracer(final OperationTracer tracer) throws IOException {
              if (outputStreams.containsKey(tracer)) {
                outputStreams.remove(tracer).close();
              }
            }
Constructor for the T8nSubCommand class with a parent command. This constructor is required by
PicoCLI.

@param parentCommand The parent command for this sub command.
ethereum/evmtool/src/main/java/org/hyperledger/besu/evmtool/T8nSubCommand.java