new_contents: #!/usr/bin/python3.4
  # -*-coding:Utf-8 -*
  '''module to manage tiles sizes'''
  import xml.etree.ElementTree as xmlMod
  import os
  
  class Tiles:
  	'''class to manage tiles sizes'''
  	
  	
  	def __init__(self, xml= None):
  		'''initialize tiles sizes with default value or values extracted from an xml object'''
  		if xml is None:
  			self.defaultInit()
  		else:
  			self.fromXml(xml)
  	
  	
  	
  	
  	
  	def defaultInit(self):
  		'''initialize tiles sizes with default value'''
  		
  		
  	
  	
  	
  	
  	
  	def fromXml(self, xml):
  		'''initialize tiles sizes with values extracted from an xml object'''
  		
  	
  	
  	
  	
  	
  	def toXml(self):
  		'''export tiles sizes into xml syntaxed string'''
  		
  	
  	
  	
  	
  	
  	def see(self, log):
  		'''method to see tiles sizes and access edition menu'''
  		change = False
  		log.menuIn('Tiles Sizes')
  		
  		while True:
  			os.system('clear')
  			log.print()
  			
  			print('\n')
  			self.print()
  			
  			print('''\n\n        \033[4mMenu :\033[0m
  1- Edit Cycles GPU Tiles Size
  1- Edit Cycles CPU Tiles Size
  1- Edit Blender Internal Tiles Size
  0- Quit
  
  ''')
  			choice = input().strip().lower()
  			
  			if choice in ['0', 'q', 'quit', 'cancel']:
  				log.menuOut()
  				return change
  			elif choice == '1':
  				# edit Cycles GPU Tiles Size
  				change = (self.editGPU(log) or change)
  			elif choice == '2':
  				# edit Cycles CPU Tiles Size
  				change = (self.editCPU(log) or change)
  			elif choice == '3':
  				# edit Blender Internal Tiles Size
  				change = (self.editBI(log) or change)
  			else:
  				log.error('Unvalid menu index!', False)
  	
  	
  	
  	
  	
  	def print(self, index = False, std = True):
  		'''a method to display the tiles sizes settings'''
  		
  	
  	
  	
  	
  	
  	
  	
  	
  	
  	
  
subject: implement a class to contain tiles size settings