code: def normalizeDefaultLayerName(value, font):
      
      value = normalizeLayerName(value)
      if value not in font.layerOrder:
          raise ValueError("No layer with the name '%s' exists." % value)
      return unicode(value)
docs: Normalizes default layer name.
  
      * **value** must normalize as layer name with
        :func:`normalizeLayerName`.
      * **value** must be a layer in **font**.
      * Returned value will be an unencoded ``unicode`` string.