code: def _insert(self, dom_group, idx=None, prepend=False, name=None):
          if idx and idx < 0:
              idx = 0
          if prepend:
              idx = 0
          else:
              idx = idx if idx is not None else len(self.childs)
          if dom_group is not None:
              if not isinstance(dom_group, Iterable) or isinstance(
                  dom_group, (DOMElement, str)
              ):
                  dom_group = [dom_group]
              for i_group, elem in enumerate(dom_group):
                  if elem is not None:
                      self.childs.insert(idx + i_group, elem)
                      if issubclass(elem.__class__, DOMElement):
                          elem.parent = self
                      if name:
                          setattr(self, name, elem)