def css_compressor=(compressor)
      unregister_bundle_processor 'text/css', @css_compressor if defined? @css_compressor
      @css_compressor = nil
      return unless compressor

      if compressor.is_a?(Symbol)
        @css_compressor = klass = config[:compressors]['text/css'][compressor] || raise(Error, "unknown compressor: #{compressor}")
      elsif compressor.respond_to?(:compress)
        klass = proc { |input| compressor.compress(input[:data]) }
        @css_compressor = :css_compressor
      else
        @css_compressor = klass = compressor
      end

      register_bundle_processor 'text/css', klass
    end
def css_compressor=(compressor)
      unregister_bundle_processor 'text/css', @css_compressor if defined? @css_compressor
      @css_compressor = nil
      return unless compressor

      if compressor.is_a?(Symbol)
        @css_compressor = klass = config[:compressors]['text/css'][compressor] || raise(Error, "unknown compressor: #{compressor}")
      elsif compressor.respond_to?(:compress)
        klass = proc { |input| compressor.compress(input[:data]) }
        @css_compressor = :css_compressor
      else
        @css_compressor = klass = compressor
      end

      register_bundle_processor 'text/css', klass
    end
Assign a compressor to run on `text/css` assets.

 The compressor object must respond to `compress`.