code: def main():
      setup_test_environment()
  
      skip_names = sys.argv[1:]
  
      # SIGUSR2 is used by test_tool to teardown tests
      if hasattr(signal, "SIGUSR2"):
          # Dump python import tracing
          import library.python.import_tracing.lib.regulator as regulator
  
          # get the original handler to return control to it after dumping
          signum = signal.SIGUSR2
          orig_handler = signal.getsignal(signum)
  
          if not hasattr(signal, "raise_signal"):
              # Only available for Python 3.8+
              def raise_signal(signum):
                  os.kill(os.getpid(), signum)
  
          else:
              raise_signal = signal.raise_signal
  
          def stop_tracing_handler(s, f):
              regulator.disable(close_not_finished=True)
              signal.signal(signal.SIGUSR2, orig_handler)
              raise_signal(signum)
  
          signal.signal(signal.SIGUSR2, stop_tracing_handler)
  
      try:
          import faulthandler
      except ImportError:
          faulthandler = None
  
      if faulthandler:
          # Dump python backtrace in case of any errors
          faulthandler.enable()
          if hasattr(signal, "SIGUSR2"):
              # SIGUSR2 is used by test_tool to teardown tests
              faulthandler.register(signal.SIGUSR2, chain=True)
  
      os.environ["Y_PYTHON_IMPORT_TEST"] = ""
  
      # We should initialize Django before importing any applications
      if os.getenv("DJANGO_SETTINGS_MODULE"):
          try:
              import django
          except ImportError:
              pass
          else:
              django.setup()
  
      py_main = __res.find("PY_MAIN")
  
      if py_main:
          py_main_module = py_main.split(b":", 1)[0].decode("UTF-8")
      else:
          py_main_module = None
  
      try:
          check_imports(no_check=skip_names, py_main=py_main_module)
      except Exception:
          sys.exit(1)
  
file_path: catboost/library/python/testing/import_test/import_test.py
imports: from __future__ import print_function
  import os
  import re
  import sys
  import time
  import signal
  import traceback
  import warnings
  import __res
  from __res import importer
label_desc: Use image node_id 3 for calling a global function with example usage: main() without return types