code: def start_event(self, modname, filename, tid=None):
      tid = tid if tid is not None else threading.current_thread().name
      time_from_start = self._get_current_time_from_start()
  
      new_event = events.Event(
          modname=modname,
          filename=filename,
          tid=tid,
          start_time=time_from_start,
          end_time=None,
      )
  
      self.events[modname] = new_event
  
file_path: catboost/library/python/import_tracing/lib/import_tracer.py
imports: import threading
  import time
  import collections
  import library.python.import_tracing.lib.event
  import library.python.import_tracing.lib.constants
label_desc: Use image node_id 2 for calling the ImportTracer obj's underlying member method code with example usage: obj.start_event(modname, filename, tid) without return types