Simple code to test Arduino to Python serial communication

py-arduino.py

#!/usr/bin/python
# -*- coding: utf-8 -*-
"""
	Sample code to test Arduino to Python serial communication
"""

import serial

error_message="################ !!! Communication Error !!! ################\n"

def mainloop():
	while True:
		try:
			try:
				#Create a connection with Arduino board and set 1 sec timeout		 
				conn = serial.Serial('/dev/ttyUSB0', timeout=1)
				tbytes = raw_input('Write something (exit does what you think): ') + '\n'
				if tbytes == 'exit\n' :
					break
				conn.write(tbytes)
				print '\n' + 'Arduino received: ' + conn.readline()
			except serial.SerialException:
				raw_input(error_message)
				break
		except KeyboardInterrupt:
			conn.close()
			break

if __name__ == '__main__':
	mainloop()