code: def is_manifest_valid(self, manifest_id):
          
          response = self.get_manifest_validation_result(manifest_id)
          if response.status_code != 200:
              raise Exception(response.status_code)
          content = json.loads(response.content)
          if not content['processed']:
              return None
          if content['valid']:
              return True
          return content['validation']
docs: Check validation shortcut
  
          :param: manifest_id (string) id received in :method:`validate_manifest`
          :returns:
              * True if manifest was valid
              * None if manifest wasn't checked yet
              * validation dict if not valid