def runner(klass)
      run do |opts, args, cmd|
        klass.new(opts, args, cmd).call
      end
    end
def runner(klass)
      run do |opts, args, cmd|
        klass.new(opts, args, cmd).call
      end
    end
Defines the runner class for this command. Calling this will override
 existing run block or runner declarations (using {#run} and {#runner},
 respectively).

 @param [Class<CommandRunner>] klass The command runner class (subclass
   of {CommandRunner}) that is used for executing this command.

 @return [void]