code: def _getLayer(self, name, **kwargs):
          
          for glyph in self.layers:
              if glyph.layer.name == name:
                  return glyph
          raise ValueError("No layer named '%s' in glyph '%s'."
                           % (name, self.name))
docs: name will be a string, but there may not be a
          layer with a name matching the string. If not,
          a ``ValueError`` must be raised.
  
          Subclasses may override this method.