code: def callback_log(callback, api_key):
      
      params = {'key': api_key, 'callback': callback}
      resource = 'v2/receive/callback_log?' + util.urlencode(params)
      resp = util.call_api(resource, base_url='https://api.blockchain.info/')
      json_resp = json.loads(resp)
      return [LogEntry(e['callback'], e['called_at'], e['raw_response'], e['response_code']) for e in json_resp]
docs: Call the 'v2/receive/callback_log' endpoint and returns the callback log
      for a given callback URI with parameters.
  
      :param callback: callback URI
      :param api_key: Blockchain.info API V2 key
      :return: a list of :class:`LogEntry` objects