Read and validate a XML file with lxml in Python.

FromXML.py

	class foo:
    @classmethod
	  def FromFile(cls, filePath):
		  if (not filePath.exists()):
        raise PyIpxactException("File '{0!s}' not found.".format(filePath))
          from FileNotFoundError(str(filePath))
		
		  try:
			  with filePath.open(encoding="utf-8") as fileHandle:
				  content = fileHandle.read()
  				content = bytes(bytearray(content, encoding='utf-8'))
	  	except OSError as ex:
		  	raise PyIpxactException("Couldn't open '{0!s}'.".format(filePath))
          from ex
		
		  os.chdir("../lib/schema")
		  schemaPath = Path("index.xsd")
  		try:
	  		with schemaPath.open(encoding="utf-8") as fileHandle:
		  		schema = fileHandle.read()
			  	schema = bytes(bytearray(schema, encoding='utf-8'))
  		except OSError as ex:
	  		raise PyIpxactException("Couldn't open '{0!s}'.".format(schemaPath))
          from ex
		
  		xmlParser =     etree.XMLParser(remove_blank_text=True, encoding="utf-8")
	  	schemaRoot =    etree.XML(schema, xmlParser)
      schemaTree =    etree.ElementTree(schemaRoot)
		  xmlSchema =     etree.XMLSchema(schemaTree)
  		documentRoot =  etree.XML(content, xmlParser)
      if (not xmlSchema.validate(documentRoot)):
			  raise PyIpxactException("The input IP-XACT file is not valid.")
      
	  	rootTag =       etree.QName(documentRoot.tag)
		  print(rootTag.localname)