old_contents: ''' Very Large Number Multiplicator
  	based on "Vedic Mathematics"
  
  	__author__: Suhovan Mandal
  	__license__: "MIT license"
  	__email__: mandal.sushovan92@gmail.com
  	__site__: www.github.com/enlighter
  '''
  
  import sys
  
  ### Pre-processing python version check ###
  req_version = (3,4)
  cur_version = sys.version_info
  
  if cur_version < req_version:
     print("Your Python interpreter is too old. Please consider upgrading.")
     exit()
  ############################################
  
  def multiply(num1=0, num2=0):
  	operand1 = str(num1)
  	operand2 = str(num2)
  	len1 = len(operand1)
  	len2 = len(operand2)
  	#debug
  	print("%s of length %d" %(operand1,len1))
  	print("%s of length %d" %(operand2,len2))
  
  	if len1 <= len2:
  		# operand1 is the shorter string
  		result,left_over = _common_iteration_multiplication(operand1, operand2)
  	else:
  		# operand2 is the shorter string
  		result,left_over = _common_iteration_multiplication(operand2, operand1)
  
  	for c in operand1[::-1]:
  		print(c)
  
  def _common_iteration_multiplication(operand1, operand2):
  	pass
  
  multiply(123, 4567)
new_contents: ''' Very Large Number Multiplicator
  	based on "Vedic Mathematics"
  
  	__author__: Suhovan Mandal
  	__license__: "MIT license"
  	__email__: mandal.sushovan92@gmail.com
  	__site__: www.github.com/enlighter
  '''
  
  import sys
  
  ### Pre-processing python version check ###
  req_version = (3,4)
  cur_version = sys.version_info
  
  if cur_version < req_version:
  	print("Your Python interpreter is too old. Please consider upgrading.")
  	exit()
  ############################################
  
  from time import process_time
  
  # def _listize_number_(num):
  # 	return_list = []
  # 	while
  
  def multiply(num1=0, num2=0):
  	if (not isinstance(num1, int)) or (not isinstance(num2,int)):
  		raise ValueError("this function only works on integers")
  
  	start_time = process_time()
  	operand1 = str(num1)
  	operand2 = str(num2)
  	len1 = len(operand1)
  	len2 = len(operand2)
  	#debug
  	print("%s of length %d" %(operand1,len1))
  	print("%s of length %d" %(operand2,len2))
  
  	temp = num1
  	num1_list = []
  	while (not temp==0):
  		num1_list.append(temp%10)
  		temp = int(temp/10)
  	print(num1_list)
  
  	if len1 <= len2:
  		# operand1 is the shorter string
  		result,left_over = _common_iteration_multiplication(operand1, operand2)
  	else:
  		# operand2 is the shorter string
  		result,left_over = _common_iteration_multiplication(operand2, operand1)
  
  	for c in operand1[::-1]:
  		print(c)
  
  	elapsed_time = process_time() - start_time
  	print("elapsed time = %f",elapsed_time)
  
  def _common_iteration_multiplication(operand1, operand2):
  	pass
  	return 0,0
  
  multiply(123, 4567)
subject: raise valueerror if input values are not integers, check listize logic