def interline_spacing(space)
      begin
        Float(space)
      rescue ArgumentError
        Kernel.raise ArgumentError, 'invalid value for interline_spacing'
      rescue TypeError
        Kernel.raise TypeError, "can't convert #{space.class} into Float"
      end
      primitive "interline-spacing #{space}"
    end
def interline_spacing(space)
      begin
        Float(space)
      rescue ArgumentError
        Kernel.raise ArgumentError, 'invalid value for interline_spacing'
      rescue TypeError
        Kernel.raise TypeError, "can't convert #{space.class} into Float"
      end
      primitive "interline-spacing #{space}"
    end
IM 6.5.5-8 and later