code: def get_children_tag_names(self, xml_element):
          
          tags = set()
          tags.add(self.remove_namespace_from_tag(xml_element.tag))
  
          for element in xml_element.iter(tag=etree.Element):
              if element != xml_element:
                  new_tags = self.get_children_tag_names(element)
                  if new_tags is not None:
                      tags.update(new_tags)
          return tags
docs: Returns all tag names of xml element and its children.