code: def normalizeGroupValue(value):
      
      if not isinstance(value, (tuple, list)):
          raise TypeError("Group value must be a list, not %s."
                          % type(value).__name__)
      value = [normalizeGlyphName(v) for v in value]
      return tuple([unicode(v) for v in value])
docs: Normalizes group value.
  
      * **value** must be a ``list``.
      * **value** items must normalize as glyph names with
        :func:`normalizeGlyphName`.
      * Returned value will be a ``tuple`` of unencoded ``unicode`` strings.