docs: def uninstall_signal_trap(signums = None):
  	"""
  	Undo the effects of install_signal_trap().  Restores the original
  	signal handlers.  If signums is a sequence of signal numbers only
  	the signal handlers for those signals will be restored (KeyError
  	will be raised if one of them is not one that install_signal_trap()
  	installed a handler for, in which case some undefined number of
  	handlers will have been restored).  If signums is None (the
  	default) then all signals that have been modified by previous calls
  	to install_signal_trap() are restored.
  
  	Note:  this function is called by put_connection_filename() and
  	discard_connection_filename() whenever they remove a scratch file
  	and there are then no more scrach files in use.
  	"""
  	# NOTE:  this must be called with the temporary_files_lock held.
  	if signums is None:
  		signums = origactions.keys()
  	for signum in signums:
  		signal.signal(signum, origactions.pop(signum))