code: def renderer(name):
      
      try:
          if name not in Store.renderers:
              extension(name)
          return Store.renderers[name]
      except ImportError:
          msg = ('Could not find a {name!r} renderer, available renderers are: {available}.')
          available = ', '.join(repr(k) for k in Store.renderers)
          raise ImportError(msg.format(name=name, available=available))
docs: Helper utility to access the active renderer for a given extension.