code: def _appendComponent(self, baseGlyph, transformation=None, identifier=None, **kwargs):
          
          pointPen = self.getPointPen()
          pointPen.addComponent(baseGlyph, transformation=transformation, identifier=identifier)
          return self.components[-1]
docs: baseGlyph will be a valid glyph name.
          The baseGlyph may or may not be in the layer.
  
          offset will be a valid offset (x, y).
          scale will be a valid scale (x, y).
          identifier will be a valid, nonconflicting identifier.
  
          This must return the new component.
  
          Subclasses may override this method.