docs: def debug_break(sig, frame):
      """Interrupt running process, and provide a python prompt for interactive
      debugging."""
      d = {'_frame': frame}         # Allow access to frame object.
      d.update(frame.f_globals)  # Unless shadowed by global
      d.update(frame.f_locals)
  
      i = code.InteractiveConsole(d)
      message = "Signal recieved : entering python shell.\nTraceback:\n"
      message += ''.join(traceback.format_stack(frame))
      i.interact(message)