code: def _properties_element(self, parent_element):
          
          requirements_properties = etree.SubElement(parent_element, "properties")
  
          req_properties_conf = self.config.get("requirements_import_properties") or {}
          for name, value in sorted(six.iteritems(req_properties_conf)):
              if name == "lookup-method":
                  lookup_prop = str(value).lower()
                  if lookup_prop not in ("id", "name"):
                      raise Dump2PolarionException(
                          "Invalid value '{}' for the 'lookup-method' property".format(str(value))
                      )
                  self._lookup_prop = lookup_prop
              else:
                  etree.SubElement(
                      requirements_properties, "property", {"name": name, "value": str(value)}
                  )
  
          return requirements_properties
docs: Returns properties XML element.