code: def is_dsub_operation(cls, op):
      
      if not cls.is_pipelines_operation(op):
        return False
  
      for name in ['job-id', 'job-name', 'user-id']:
        if not cls.get_operation_label(op, name):
          return False
  
      return True
docs: Determine if a pipelines operation is a dsub request.
  
      We don't have a rigorous way to identify an operation as being submitted
      by dsub. Our best option is to check for certain fields that have always
      been part of dsub operations.
  
      - labels: job-id, job-name, and user-id have always existed
      - envs: _SCRIPT has always existed.
  
      In order to keep a simple heuristic this test only uses labels.
      Args:
        op: a pipelines operation.
  
      Returns:
        Boolean, true if the pipeline run was generated by dsub.