code: def clear(self):
          ''' Remove all content from the document but do not reset title.
  
          Returns:
              None
  
          '''
          self._push_all_models_freeze()
          try:
              while len(self._roots) > 0:
                  r = next(iter(self._roots))
                  self.remove_root(r)
          finally:
              self._pop_all_models_freeze(f clear(self):
          ''' Remove all content from the document but do not reset title.
  
          Returns:
              None
  
          '''
          self._push_all_models_freeze()
          try:
              while len(self._roots) > 0:
                  r = next(iter(self._roots))
                  self.remove_root(r)
          finally:
              self._pop_all_models_freeze()
docs: Remove all content from the document but do not reset title.
  
          Returns:
              None