class_docstr: Base class of function operation that will execute StatelessFunction or StatefulFunction for
  each input element.
class_docstr_tok: ["Base","class","of","function","operation","that","will","execute","StatelessFunction","or","StatefulFunction","for","each","input","element","."]
code: def progress_metrics(self):
      metrics = super(FunctionOperation, self).progress_metrics()
      metrics.processed_elements.measured.output_element_counts.clear()
      tag = None
      receiver = self.receivers[0]
      metrics.processed_elements.measured.output_element_counts[
          str(tag)
      ] = receiver.opcounter.element_counter.value()
      return metrics
  
imports: import abc
  from abc import abstractmethod
  from typing import Iterable, Any, Dict, List
  from apache_beam.runners.worker.bundle_processor import TimerInfo, DataOutputOperation
  from apache_beam.runners.worker.operations import Operation
  from apache_beam.utils import windowed_value
  from apache_beam.utils.windowed_value import WindowedValue
  from pyflink.common.constants import DEFAULT_OUTPUT_TAG
  from pyflink.fn_execution.flink_fn_execution_pb2 import UserDefinedDataStreamFunction
  from pyflink.fn_execution.table.operations import BundleOperation
  from pyflink.fn_execution.profiler import Profiler
label_desc: Use image node_id 8 for calling the FunctionOperation obj's underlying member method code with example usage: obj.progress_metrics() and returns: metrics