    # File lib/compass/sass_extensions/functions/gradient_support.rb, line 10
        def initialize(color, stop = nil)
          unless Sass::Script::Color === color ||
                 Sass::Script::Funcall === color ||
                 (Sass::Script::String === color && color.value == "transparent")
            raise Sass::SyntaxError, "Expected a color. Got: #{color}"
          end
          if stop && !stop.is_a?(Sass::Script::Number)
            raise Sass::SyntaxError, "Expected a number. Got: #{stop}"
          end
          self.color, self.stop = color, stop
        end