new_contents: 
  # Chechinput: returns false is the inputed text 
  # has any numeric character
  
  def checkInput(userInput):
  	return userInput.isalpha()
   
  # CheckNumber: returns false is the inputed text 
  # has any numeric character
  
  def checkNumber(userInput):
  	return userInput.isdigit()
  
  def readMessage():
  	valid = False; 
  	message = '';
  	while(not valid):
  		# Iterate until input message has not have any numeric element (number)
  		message = raw_input('Introduce your message: ');
  		valid = checkInput(message);
  
  	return message;
  
  # Now, let the user inputs the desired shift number
  # iterates until inputed number is correct.
  
  def readNumber():
  	valid = False;
  	number = -1;
  	while(not valid):
  		number = raw_input('Introduce your shift Number: ');
  		valid = checkNumber(number);
  		if (not valid):
  			print 'Come on! this is not a number :P'; 
  
  	return number;
  
  # Returns and object with a message and a number.
  
  def userInput(): 
  	message = readMessage();
  	number = readNumber(); 
  
  	# Compose and object and returns to the user
  	userInput = {'message': message, 'number': number};
  	return userInput;
  
  def simpleEncription(message, shiftNumber):
  	
  	if (type(shiftNumber) is not int):
  		shiftNumber = int(shiftNumber); # Int casting of shiftNumber when typed is not expressed as integer. Sometimes may ocurr the program interprets a string...
  	
  	auxChar = '';
  	encriptedMsg = list();
  	shiftNumber = shiftNumber % 26; # English alfhabet has 26 elements. when user shifs more than 26, then make the modulus! if not, an error will crash lines below.
  
  	# Convert each character of the array into a
  	# number, then sum the shif and finally convert this
  	# number into the alfabhet letter corresponding.
  	 
  	for char in message:
  		
  		if (char == 'z'):
  			auxChar = ord('a') - 1;
  		elif (char == 'Z'):
  			auxChar = ord('A') - 1;
  		else:
  			auxChar = ord(char);
  
  		auxChar += shiftNumber;
  		encriptedChar = chr(auxChar);
  		encriptedMsg.append(encriptedChar);
  
  	return encriptedMsg;
  
  
  userInput = userInput(); # Returns a valid message and shif number from user in a list.
  message = userInput['message']; # Local variable for the message inputed by the user
  number = userInput['number']; # Local variable for the number inputed by the user
  
  encriptedMsgList = simpleEncription(message, number);
  
  print encriptedMsgList
  
  outputMsg = '';
  for index, char in enumerate(encriptedMsgList):
  	outputMsg += char;
  
  print outputMsg
  
subject: Create cesarEncription.py