a simple tcp client(python code)

tcpClient1.py

#! /usr/bin/python
# a simple tcp client
import socket  
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  
sock.connect(('127.0.0.1', 12345))  
#sock.send('Test\n')  
sock.send(raw_input("Please input : "))  
print sock.recv(1024)
sock.close()

what does raw_input do ?