Python script to parse xml ovf files

parse_xml.py

import xml.etree.ElementTree as ET


def itemNumber(search_item_text):
	count = 0 
	count2 = 0
	print('searching:', search_item_text)
	for var in root.findall('a:VirtualSystem/b:VirtualHardwareSection', ns):
		#print(var.tag, var.text)
		for desc in var.findall('c:Item/d:Description', ns):
			count = count + 1
			if desc.text == search_item_text:
			   print('found in count:', count)
			   count2 = count
	return count2


def register_all_namespaces(filename):
#
# This method will preserv all namespaces and must be called before write
# source: https://stackoverflow.com/questions/54439309/how-to-preserve-namespaces-when-parsing-xml-via-elementtree-in-python
#
    namespaces = dict([node for _, node in ET.iterparse(filename, events=['start-ns'])])
    for ns in namespaces:
        ET.register_namespace(ns, namespaces[ns])
	


def replaceItem(replace_item, new_value):
	item_number = str(itemNumber(replace_item))
	search_str = ".//a:VirtualSystem/b:VirtualHardwareSection/c:Item[" + item_number + "]/d:VirtualQuantity"
	
	current_value = root.find(search_str, ns)
	
	if current_value.text == new_value :
		print('Info: Nothing to do. Current and New are the same')
		print ('current value:' , current_value.text, ' --  new value:', new_value)
	else:
		current_value.text = new_value
		register_all_namespaces(sourceFile)
		tree.write(targetFile)
		# checking on target file
		tree2 = ET.parse(targetFile)
		root2 = tree2.getroot()
		current_value2 = root2.find(search_str, ns)
		if current_value2.text == new_value:
			print(replace_item, '.. replaced ok')
		else:
			print("Error: this is not good")



# ------
# main
# ------
sourceFile = "desc.ovf"
targetFile = "otro.xml"

tree = ET.parse(sourceFile)
root = tree.getroot()

#for var in root.findall('./{http://schemas.dmtf.org/ovf/envelope/1}VirtualSystem/{http://schemas.dmtf.org/ovf/envelope/1}VirtualHardwareSection/{http://schemas.dmtf.org/ovf/envelope/1}Item/{http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/CIM_ResourceAllocationSettingData}VirtualQuantity'):

ns = {'a':'http://schemas.dmtf.org/ovf/envelope/1' , 
'b': 'http://schemas.dmtf.org/ovf/envelope/1' , 
'c': 'http://schemas.dmtf.org/ovf/envelope/1',
'd': 'http://schemas.dmtf.org/wbem/wscim/1/cim-schema/2/CIM_ResourceAllocationSettingData'}

replaceItem('Memory Size', '8192')