old_contents: #!/usr/bin/python3
  
  # Echo client program
  import socket
  
  HOST = '192.168.1.138'    # The remote host
  PORT = 50007              # The same port as used by the server
  s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  s.connect((HOST, PORT))
  s.sendall(b'Hello, world')
  data = s.recv(1024)
  s.close()
  print('Received', repr(data))
  
new_contents: #!/usr/bin/python3
  
  # Echo client program
  import socket
  
  HOST = 'localhost'    # The remote host
  PORT = 50007              # The same port as used by the server
  s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  s.connect((HOST, PORT))
  s.sendall(b'Hello, world')
  data = s.recv(1024)
  s.close()
  print('Received', repr(data))
  
subject: fix wrong hostname