code: def get_job_definition(self, identifier):
          
          env = self.get_job_definition_by_arn(identifier)
          if env is None:
              env = self.get_job_definition_by_name(identifier)
          return env
docs: Get job defintiion by name or ARN
          :param identifier: Name or ARN
          :type identifier: str
  
          :return: Job definition or None
          :rtype: JobDefinition or None