code: def __exit__(self, exc_type, exc_value, traceback):
      end_time = time.perf_counter_ns()
      run_time = (end_time - self.__start_time) / 1e9
      if self.__end_msg:
          output = self.__end_msg + f"{run_time}s\n"
      else:
          output = f"DONE {self.__label}, runtime was: {run_time}s\n"
      self.__handle.write(output)
      self.__handle.flush()
  
imports: import sys
  import time
label_desc: Use image node_id 3 for calling the TimerContext obj's underlying member method code with example usage: obj.__exit__(exc_type, exc_value, traceback) without return types