code: def extract_timestamp(self, value, record_timestamp) -> int:
      return int(value[1])
  
file_path: flink/flink-python/pyflink/examples/datastream/windowing/sliding_time_window.py
imports: import sys
  import argparse
  from typing import Iterable
  from pyflink.datastream.connectors.file_system import FileSink, OutputFileConfig, RollingPolicy
  from pyflink.common import Types, WatermarkStrategy, Time, Encoder
  from pyflink.common.watermark_strategy import TimestampAssigner
  from pyflink.datastream import StreamExecutionEnvironment, ProcessWindowFunction
  from pyflink.datastream.window import SlidingEventTimeWindows, TimeWindow
label_desc: Use image node_id 1 for calling the MyTimestampAssigner obj's underlying member method code with example usage: obj.extract_timestamp(value, record_timestamp) and returns: int