code: public Command get(String commandName, boolean forceCreate) {
          Command command = commands.get(commandName);
          
          if (command == null && forceCreate) {
              command = new Command(commandName);
              add(command);
          }
          
          return command;
      }
docs: Retrieves the command associated with the specified name from the registry.
  
  @param commandName Name of the command sought.
  @param forceCreate If true and the command does not exist, one is created and added to the
  registry.
  @return The associated command, or null if it does not exist (and forceCreate is false).