code: def explain(code, signals=SIGNALS):
      
      if code not in signals:
          raise NoSuchSignal(code)
      signal, action, description = signals[code]
      return {
          'id': code,
          'signal': signal,
          'action': action,
          'description': description,
          }
docs: Explain what a given integer signal *code* does,
      including it's signal name.
  
      :param code: An integer signal.
      :param signals: A database of signals.