old_contents: from twisted.internet import endpoints, protocol, reactor
  
  class UpperProtocol(protocol.Protocol):
      def connectionMade(self):
          self.transport.write('Hi! Send me some text to convert to uppercase\n')
  
  factory = protocol.ServerFactory()
  factory.protocol = UpperProtocol
  
  endpoints.serverFromString(reactor, 'tcp:8000').listen(factory)
  reactor.run()
  
new_contents: from twisted.internet import endpoints, protocol, reactor
  
  class UpperProtocol(protocol.Protocol):
      def connectionMade(self):
          self.transport.write('Hi! Send me some text to convert to uppercase\n')
  
      def dataReceived(self, data):
          self.transport.write(data.upper())
  
  factory = protocol.ServerFactory()
  factory.protocol = UpperProtocol
  
  endpoints.serverFromString(reactor, 'tcp:8000').listen(factory)
  reactor.run()
  
subject: Implement response with uppercase received data