code: def get_s3_client(self) -> luigi.contrib.s3.S3Client:
      if self._client is None:  # use cache as like singleton object
          self._client = self._get_s3_client()
      return self._client
  
imports: import os
  import luigi
  import luigi.contrib.s3
label_desc: Use image node_id 1 for calling the S3Config obj's underlying member method code with example usage: obj.get_s3_client() and returns: self