class_docstr: Timer class for recording elapsed wall time in operations.
class_docstr_tok: ["Timer","class","for","recording","elapsed","wall","time","in","operations","."]
code: def elapsed(self):
      stop = self.stop_time
      if stop is None:
          stop = time.perf_counter()
  
      return stop - self.start_time
  
imports: import time
label_desc: Use image node_id 4 for calling the Stopwatch obj's underlying member method code with example usage: obj.elapsed() and returns: unknown