This is the environment implementation of
        :meth:`BaseObject.scaleBy`.

        **value** will be an iterable containing two
        :ref:`type-int-float` values defining the x and y
        values to scale the object by. It will have been
        normalized with :func:`normalizers.normalizeTransformationScale`.
        **origin** will be a :ref:`type-coordinate` defining
        the point at which the scale should orginate.

        Subclasses may override this method.

def _scaleBy(self, value, origin=None, **kwargs):
        """
        This is the environment implementation of
        :meth:`BaseObject.scaleBy`.

        **value** will be an iterable containing two
        :ref:`type-int-float` values defining the x and y
        values to scale the object by. It will have been
        normalized with :func:`normalizers.normalizeTransformationScale`.
        **origin** will be a :ref:`type-coordinate` defining
        the point at which the scale should orginate.

        Subclasses may override this method.
        """
        x, y = value
        t = transform.Identity.scale(x=x, y=y)
        self.transformBy(tuple(t), origin=origin, **kwargs)