text: import os, sys
  import imp
  
  from authorizenet import apicontractsv1
  from authorizenet.apicontrollers import *
  constants = imp.load_source('modulename', 'constants.py')
  from decimal import *
  
  def void(refTransId):
      merchantAuth = apicontractsv1.merchantAuthenticationType()
      merchantAuth.name = constants.apiLoginId
      merchantAuth.transactionKey = constants.transactionKey
  
      paypal = apicontractsv1.payPalType()
  
      payment = apicontractsv1.paymentType()
      payment.payPal = paypal
  
      transactionrequest = apicontractsv1.transactionRequestType()
      transactionrequest.transactionType = apicontractsv1.transactionTypeEnum.voidTransaction
      transactionrequest.refTransId = refTransId
      transactionrequest.payment = payment
  
      request = apicontractsv1.createTransactionRequest()
      request.merchantAuthentication = merchantAuth
      request.refId = "Sample"
      request.transactionRequest = transactionrequest
  
      controller = createTransactionController(request)
      controller.execute()
  
      response = controller.getresponse()
  
      if response is not None:
          if response.messages.resultCode == "Ok":
              if hasattr(response.transactionResponse, 'messages') == True:
                  print ('Successfully created transaction with Transaction ID: %s' % response.transactionResponse.transId)  
                  print ('Transaction Response Code: %s' % response.transactionResponse.responseCode)  
                  print ('Message Code: %s' % response.transactionResponse.messages.message[0].code)  
                  print ('Description: %s' % response.transactionResponse.messages.message[0].description)  
              else:
                  print ('Failed Transaction.')  
                  if hasattr(response.transactionResponse, 'errors') == True:
                      print ('Error Code:  %s' % str(response.transactionResponse.errors.error[0].errorCode))  
                      print ('Error message: %s' % response.transactionResponse.errors.error[0].errorText)  
          else:
              print ('Failed Transaction.')  
              if hasattr(response, 'transactionResponse') == True and hasattr(response.transactionResponse, 'errors') == True:
                  print ('Error Code: %s' % str(response.transactionResponse.errors.error[0].errorCode))  
                  print ('Error message: %s' % response.transactionResponse.errors.error[0].errorText)  
              else:
                  print ('Error Code: %s' % response.messages.message[0]['code'].text)  
                  print ('Error message: %s' % response.messages.message[0]['text'].text)  
      else:
          print ('Null Response.')  
  
      return response
  
  if(os.path.basename(__file__) == os.path.basename(sys.argv[0])):
      void(constants.transactionId)
  