code: def close(self):
      if self._msg_buffer:
          self._print("".join(self._msg_buffer), sep="", end="\n")
          self._msg_buffer.clear()
  
file_path: flink/flink-python/pyflink/fn_execution/beam/beam_sdk_worker_main.py
imports: import sys
  import pyflink.fn_execution.beam.beam_operations
  import pyflink.fn_execution.beam.beam_coders
  import apache_beam.runners.worker.sdk_worker_main
  from apache_beam.runners.worker import sdk_worker
label_desc: Use image node_id 3 for calling the CustomPrint obj's underlying member method code with example usage: obj.close() without return types