docs: def load(self, record_key, secret_key=''):
  
          ''' 
              a method to retrieve byte data of appdata record
  
          :param record_key: string with name of record
          :param secret_key: [optional] string used to decrypt data
          :return: byte data for record body
          '''
  
          title = '%s.load' % self.__class__.__name__
      
      # validate inputs
          input_fields = {
              'record_key': record_key,
              'secret_key': secret_key
          }
          for key, value in input_fields.items():
              if value:
                  object_title = '%s(%s=%s)' % (title, key, str(value))
                  self.fields.validate(value, '.%s' % key, object_title)
  
      # verify permissions
          if not self.permissions_content:
              raise Exception('%s requires an access_token with file content permissions.' % title)
              
      # retrieve file id
          file_id, parent_id = self._get_id(record_key)
          if not file_id:
              raise Exception('%s(record_key=%s) does not exist.' % (title, record_key))
      
      # request file data
          try:
              record_data = self.drive.get_media(fileId=file_id).execute()
          except:
              raise DriveConnectionError(title)
      
      # retrieve data from response
      #     import io
      #     from googleapiclient.http import MediaIoBaseDownload
      #     file_header = io.BytesIO
      #     record_data = MediaIoBaseDownload(file_header, response)
      #     done = False
      #     while not done:
      #         status, done = record_data.next_chunk()
      
      # TODO export google document to other format
              
      # decrypt (if necessary)
          if secret_key:
              from labpack.encryption import cryptolab
              record_data = cryptolab.decrypt(record_data, secret_key)
      
          return record_data