_getHelpCommand() {
    const hasImplicitHelpCommand =
      this._addImplicitHelpCommand ??
      (this.commands.length &&
        !this._actionHandler &&
        !this._findCommand('help'));

    if (hasImplicitHelpCommand) {
      if (this._helpCommand === undefined) {
        this.helpCommand(undefined, undefined); // use default name and description
      }
      return this._helpCommand;
    }
    return null;
  }
Lazy create help command.

@return {(Command|null)}
@package