old_contents: '''
      Simple echo server
  '''
  import wlan
  import socket
  import select
  import led, time
  
  SSID=''     # Network SSID
  KEY=''      # Network key
  HOST = ''   # Use first available interface
  PORT = 8000 # Arbitrary non-privileged port
  
  led.off(led.RED)
  led.off(led.BLUE)
  led.on(led.GREEN)
  
  # Init wlan module and connect to network
  wlan.init()
  wlan.connect(SSID, sec=wlan.WPA2, key=KEY)
  led.off(led.GREEN)
  
  # Wait for connection to be established
  while (True):
      led.toggle(led.BLUE)
      time.sleep(250)
      led.toggle(led.BLUE)
      time.sleep(250)
      if wlan.connected():
          led.on(led.BLUE)
          break;
  
  # We should have a valid IP now via DHCP
  wlan.ifconfig()
  
  # Create server socket
  s = socket.socket(socket.AF_INET, socket.SOCK_STREAM, socket.IPPROTO_TCP)
  
  # Set socket in blocking mode
  s.setblocking(True)
  
  # Bind and listen
  s.bind((HOST, PORT))
  s.listen(5)
  
  while(True):
      print ('Waiting for connections..')
      client, addr = s.accept()
      print ('Connected to ' + addr[0] + ':' + str(addr[1]))
  
      # Set client socket non-blocking
      client.setblocking(False)
  
      while (True):
          rfds, wfds, xfds = select.select([client], [], [client], 1.0)
          if xfds:
              print("socket exception")
              break
          elif rfds:
              buf = client.recv(1024)
              if len(buf) == 0: # peer has shutdown
                  print("socket closed")
                  client.close()
                  break
              print ("recv:"+buf)
              client.send(buf)
          elif wfds:
              print ("wfds")
          else:
              print ("timeout")
  
new_contents: '''
      Simple echo server
  '''
  import wlan
  import socket
  import select
  import led, time
  
  SSID=''     # Network SSID
  KEY=''      # Network key
  HOST = ''   # Use first available interface
  PORT = 8000 # Arbitrary non-privileged port
  
  led.off(led.RED)
  led.off(led.BLUE)
  led.on(led.GREEN)
  
  # Init wlan module and connect to network
  wlan.init()
  wlan.connect(SSID, sec=wlan.WPA2, key=KEY)
  led.off(led.GREEN)
  
  # Wait for connection to be established
  while (True):
      led.toggle(led.BLUE)
      time.sleep(250)
      led.toggle(led.BLUE)
      time.sleep(250)
      if wlan.connected():
          led.on(led.BLUE)
          break;
  
  # We should have a valid IP now via DHCP
  wlan.ifconfig()
  
  # Create server socket
  s = socket.socket(socket.AF_INET, socket.SOCK_STREAM, socket.IPPROTO_TCP)
  
  # Set socket in blocking mode
  s.setblocking(True)
  
  # Bind and listen
  s.bind((HOST, PORT))
  s.listen(5)
  
  while(True):
      print ('Waiting for connections..')
      client, addr = s.accept()
      print ('Connected to ' + addr[0] + ':' + str(addr[1]))
  
      # Set client socket non-blocking
      client.setblocking(False)
  
      while (True):
          rfds, wfds, xfds = select.select([client], [], [client], 1.0)
          if xfds:
              print("socket exception")
              break
          elif rfds:
              buf = client.recv(1024)
              if len(buf) == 0: # peer has shutdown
                  print("socket closed")
                  client.close()
                  break
              print ("recv:"+str(buf))
              client.send(buf)
          elif wfds:
              print ("wfds")
          else:
              print ("timeout")
  
subject: Use str to convert received buffer