code: def isNonPairTag(self, isnonpair=None):
          
          if isnonpair is None:
              return self._isnonpairtag
  
          if not self._istag:
              return
  
          if isnonpair:
              self.endtag = None
              self.childs = []
  
          self._isnonpairtag = isnonpair
docs: True if element is listed in nonpair tag table (``br`` for example) or
          if it ends with ``/>`` (``<hr />`` for example).
  
          You can also change state from pair to nonpair if you use this as
          setter.
  
          Args:
              isnonpair (bool, default None): If set, internal nonpair state is
                        changed.
  
          Returns:
              book: True if tag is nonpair.