class Grape::Middleware::Stack

def merge_with(middleware_specs)

def merge_with(middleware_specs)
  middleware_specs.each do |operation, *args|
    if args.last.is_a?(Proc)
      last_proc = args.pop
      public_send(operation, *args, &last_proc)
    else
      public_send(operation, *args)
    end
  end
end