module Rack::Handler

def self.get(server)
  return unless server
  server = server.to_s
  unless @handlers.include? server
    load_error = try_require('rack/handler', server)
  end
  if klass = @handlers[server]
    const_get(klass)
  else
    const_get(server, false)
  end
rescue NameError => name_error
  raise load_error || name_error
end