code: def preview_email_marketing_campaign(self, email_marketing_campaign):
          
          url = self.api.join('/'.join([
              self.EMAIL_MARKETING_CAMPAIGN_URL,
              str(email_marketing_campaign.constant_contact_id),
              'preview']))
          response = url.get()
          self.handle_response_status(response)
          return (response.json()['preview_email_content'],
                  response.json()['preview_text_content'])
docs: Returns HTML and text previews of an EmailMarketingCampaign.