code: def _merge_ws(self, item, container):  # type: (Item, Container) -> bool
          
          last = container.last_item()
          if not last:
              return False
  
          if not isinstance(item, Whitespace) or not isinstance(last, Whitespace):
              return False
  
          start = self._idx - (len(last.s) + len(item.s))
          container.body[-1] = (
              container.body[-1][0],
              Whitespace(self._src[start : self._idx]),
          )
  
          return True
docs: Merges the given Item with the last one currently in the given Container if
          both are whitespace items.
  
          Returns True if the items were merged.