code: def validate_xml(xml, schema, debug=False):
          
  
          assert isinstance(schema, compat.str_type)
          try:
              xml = OneLogin_Saml2_XML.to_etree(xml)
          except Exception as e:
              if debug:
                  print(e)
              return 'unloaded_xml'
  
          schema_file = join(dirname(__file__), 'schemas', schema)
          with open(schema_file, 'r') as f_schema:
              xmlschema = OneLogin_Saml2_XML._schema_class(etree.parse(f_schema))
  
          if not xmlschema.validate(xml):
              if debug:
                  print('Errors validating the metadata: ')
                  for error in xmlschema.error_log:
                      print(error.message)
              return 'invalid_xml'
          return xml
docs: Validates a xml against a schema
          :param xml: The xml that will be validated
          :type xml: str|bytes|xml.dom.minidom.Document|etree.Element
          :param schema: The schema
          :type schema: string
          :param debug: If debug is active, the parse-errors will be showed
          :type debug: bool
          :returns: Error code or the DomDocument of the xml
          :rtype: xml.dom.minidom.Document