code: def scaleBy(self, factor):
          
          factor = normalizers.normalizeTransformationScale(factor)
          self._scale(factor)
docs: Scales all kerning values by **factor**. **factor** will be an
          :ref:`type-int-float`, ``tuple`` or ``list``. The first value of the
          **factor** will be used to scale the kerning values.
  
              >>> myKerning.scaleBy(2)
              >>> myKerning.scaleBy((2,3))