code: def _enter_newline(self):
          
  
          last_text_idx = self._last_text_idx
          if last_text_idx >= 0:
              buf = self._buffer
              buf[last_text_idx] = buf[last_text_idx].rstrip()
  
          self._remove_begining_ws = True
docs: Remove the trailing spaces in the current line, and then mark that the
          leading spaces of the next line need to be removed.
  
          .. seealso::
             `CSS Text Module Level 3 - The White Space Processing Rules
              <http://www.w3.org/TR/css3-text/#white-space-phase-2>`_