docs: def scaledBy(self, scale):
          """ Return a new Selector with scale denominators scaled by a number.
          """
          scaled = deepcopy(self)
      
          for test in scaled.elements[0].tests:
              if type(test.value) in (int, float):
                  if test.property == 'scale-denominator':
                      test.value /= scale
                  elif test.property == 'zoom':
                      test.value += log(scale)/log(2)
          
          return scaled