class_docstr: Handles launching, suspending signals, and potentially dealing with terminal issues.
code: def _sigusr1_handler(
      cls, signum, stack_frame
  ):  # pylint: disable=unused-argument
      assert (
          cls._STARTED_INSTANCE is not None
      ), "overridden sigusr1 handler should not be invoked when GDB not started"
      signal.signal(
          signal.SIGINT, cls._STARTED_INSTANCE.old_sigint_handler
      )
      signal.signal(
          signal.SIGUSR1, cls._STARTED_INSTANCE.old_sigusr1_handler
      )
      cls._STARTED_INSTANCE._signals_reset_event.set()
  
imports: import atexit
  import abc
  import errno
  import logging
  import os
  import shlex
  import signal
  import subprocess
  import sys
  import termios
  import threading
  import time
  import psutil
  from .._ffi import register_func
  from .None import class_factory
  from .None import transport
  from .transport.file_descriptor import FdTransport
label_desc: Use image node_id 6 for calling the GdbDebugger obj's underlying member method code with example usage: obj._sigusr1_handler(cls, signum, stack_frame) without return types