code: def _transformBy(self, matrix, **kwargs):
          
          t = transform.Transform(*matrix)
          x, y = t.transformPoint((self.x, self.y))
          self.x = x
          self.y = y
docs: This is the environment implementation of
          :meth:`BaseAnchor.transformBy`.
  
          **matrix** will be a :ref:`type-transformation`.
          that has been normalized with
          :func:`normalizers.normalizeTransformationMatrix`.
  
          Subclasses may override this method.