def comment(opts)
      opts = opts.merge(:sale_id => self.sale_id)
      Twocheckout::API.request(:post, 'sales/create_comment', opts)
    end
def comment(opts)
      opts = opts.merge(:sale_id => self.sale_id)
      Twocheckout::API.request(:post, 'sales/create_comment', opts)
    end
Add a sale comment