Interrupt running process, and provide a python prompt for interactive debugging.
    This code is based on http://stackoverflow.com/a/133384/396730

def _debug_current_process(sig, current_frame):
    """Interrupt running process, and provide a python prompt for interactive debugging.
    This code is based on http://stackoverflow.com/a/133384/396730
    """
    # Import modules only if necessary, readline is for shell history support.
    import code, traceback, readline, threading  # @UnresolvedImport @UnusedImport

    d={'_frame':current_frame}         # Allow access to frame object.
    d.update(current_frame.f_globals)  # Unless shadowed by global
    d.update(current_frame.f_locals)

    i = code.InteractiveConsole(d)
    message  = "Signal received : entering python shell.\n"

    threads = dict((thread.ident, thread) for thread in threading.enumerate())
    current_thread = threading.current_thread()
    for thread_id, frame in sys._current_frames().items():
        if current_thread.ident != thread_id:
            message += "\nTraceback of thread {}:\n".format(threads[thread_id])
            message += ''.join(traceback.format_stack(frame))
    message += "\nTraceback of current thread {}:\n".format(current_thread)
    message += ''.join(traceback.format_stack(current_frame))
    i.interact(message)