code: def default_for(self, style_type):
          
          default_styles_for_type = [
              s for s in self._iter_styles()
              if s.type == style_type and s.default
          ]
          if not default_styles_for_type:
              return None
          # spec calls for last default in document order
          return default_styles_for_type[-1]
docs: Return `w:style[@w:type="*{style_type}*][-1]` or |None| if not found.