def billet_url
      return if unpersisted?
      
      response = Http.get("/invoices/#{uuid}/billet/", domain.token)
      
      return if response.code != 200
      
      MultiJson.decode(response.body)["billet"]
    rescue
      nil
    end
def billet_url
      return if unpersisted?
      
      response = Http.get("/invoices/#{uuid}/billet/", domain.token)
      
      return if response.code != 200
      
      MultiJson.decode(response.body)["billet"]
    rescue
      nil
    end
Returns a String with the temporary URL for print current invoice.

 API method: <tt>GET /invoices/:uuid/billet/</tt>

 API documentation: https://charging.financeconnect.com.br/static/docs/charges.html#get-invoices-uuid-billet