code: @Override
      public ExecutionControl generate(ExecutionEnv env, Map<String, String> parameters) {
          return new LocalExecutionControl();
      }
docs: Create and return a locally executing {@code ExecutionControl} instance.
  
  @param env the execution environment, provided by JShell
  @param parameters the {@linkplain #defaultParameters()  default} or
  modified parameter map.
  @return the execution engine