code: def _get_base_defaultLayer(self):
          
          name = self.defaultLayerName
          layer = self.getLayer(name)
          return layer
docs: This is the environment implementation of
          :attr:`BaseFont.defaultLayer`. Return the
          default layer as a :class:`BaseLayer` object.
          The layer will be normalized with
          :func:`normalizers.normalizeLayer`.
  
          Subclasses must override this method.