code: def process_element(self, input_row: Row):
      input_value = input_row._values
      current_key = self._key_selector.get_key(input_value)
      self._state_backend.set_current_key(current_key)
      if self._window_assigner.is_event_time():
          timestamp = input_value[self._rowtime_index]
          seconds = int(
              timestamp.replace(
                  tzinfo=datetime.timezone.utc
              ).timestamp()
          )
          microseconds_of_second = timestamp.microsecond
          milliseconds = seconds * 1000 + microseconds_of_second // 1000
          timestamp = milliseconds
      else:
          timestamp = (
              self._internal_timer_service.current_processing_time()
          )
  
      timestamp = self.to_utc_timestamp_mills(timestamp)
  
      # the windows which the input row should be placed into
      affected_windows = self._window_function.assign_state_namespace(
          input_value, timestamp
      )
      for window in affected_windows:
          self._window_state.set_current_namespace(window)
          acc = self._window_state.value()  # type: List
          if acc is None:
              acc = self._window_aggregator.create_accumulators()
          self._window_aggregator.set_accumulators(window, acc)
  
          if input_row._is_accumulate_msg():
              self._window_aggregator.accumulate(input_row)
          else:
              self._window_aggregator.retract(input_row)
          acc = self._window_aggregator.get_accumulators()
          self._window_state.update(acc)
  
      # the actual window which the input row is belongs to
      actual_windows = self._window_function.assign_actual_windows(
          input_value, timestamp
      )
      result = []
      for window in actual_windows:
          self._trigger_context.window = window
          trigger_result = self._trigger_context.on_element(
              input_row, timestamp
          )
          if trigger_result:
              result.append(
                  self._emit_window_result(current_key, window)
              )
          self._register_cleanup_timer(window)
      return result
  
imports: import datetime
  from abc import ABC, abstractmethod
  from typing import TypeVar, Generic, List, Dict
  import pytz
  from pyflink.common import Row, RowKind
  from pyflink.common.constants import MAX_LONG_VALUE
  from pyflink.fn_execution.datastream.timerservice import InternalTimer
  from pyflink.fn_execution.datastream.process.timerservice_impl import LegacyInternalTimerServiceImpl
  from pyflink.fn_execution.coders import PickleCoder
  from pyflink.fn_execution.table.aggregate_slow import DistinctViewDescriptor, RowKeySelector
  from pyflink.fn_execution.table.state_data_view import DataViewSpec, ListViewSpec, MapViewSpec, PerWindowStateDataViewStore
  from pyflink.fn_execution.table.window_assigner import WindowAssigner, PanedWindowAssigner, MergingWindowAssigner
  from pyflink.fn_execution.table.window_context import WindowContext, TriggerContext, K, W
  from pyflink.fn_execution.table.window_process_function import GeneralWindowProcessFunction, InternalWindowProcessFunction, PanedWindowProcessFunction, MergingWindowProcessFunction
  from pyflink.fn_execution.table.window_trigger import Trigger
  from pyflink.table.udf import ImperativeAggregateFunction, FunctionContext
label_desc: Use image node_id 3 for calling the GroupWindowAggFunctionBase obj's underlying member method code with example usage: obj.process_element(input_row) and returns: result