code: def _load_lib():
      
      lib_paths = find_lib_path()
      if not lib_paths:
          return None
      try:
          pathBackup = os.environ['PATH'].split(os.pathsep)
      except KeyError:
          pathBackup = []
      lib_success = False
      os_error_list = []
      for lib_path in lib_paths:
          try:
              # needed when the lib is linked with non-system-available dependencies
              os.environ['PATH'] = os.pathsep.join(pathBackup + [os.path.dirname(lib_path)])
              lib = ctypes.cdll.LoadLibrary(lib_path)
              lib_success = True
          except OSError as e:
              os_error_list.append(str(e))
              continue
          finally:
              os.environ['PATH'] = os.pathsep.join(pathBackup)
      if not lib_success:
          libname = os.path.basename(lib_paths[0])
          raise XGBoostError(
              'XGBoost Library ({}) could not be loaded.\n'.format(libname) +
              'Likely causes:\n' +
              '  * OpenMP runtime is not installed ' +
              '(vcomp140.dll or libgomp-1.dll for Windows, ' +
              'libgomp.so for UNIX-like OSes)\n' +
              '  * You are running 32-bit Python on a 64-bit OS\n' +
              'Error message(s): {}\n'.format(os_error_list))
      lib.XGBGetLastError.restype = ctypes.c_char_p
      lib.callback = _get_log_callback_func()
      if lib.XGBRegisterLogCallback(lib.callback) != 0:
          raise XGBoostError(lib.XGBGetLastError())
      return lib
docs: Load xgboost Library.