code: def when_mentioned_or(*prefixes):
      
      def inner(bot, msg):
          r = list(prefixes)
          r = when_mentioned(bot, msg) + r
          return r
  
      return inner
docs: A callable that implements when mentioned or other prefixes provided.
  
      These are meant to be passed into the :attr:`.Bot.command_prefix` attribute.
  
      Example
      --------
  
      .. code-block:: python3
  
          bot = commands.Bot(command_prefix=commands.when_mentioned_or('!'))
  
  
      .. note::
  
          This callable returns another callable, so if this is done inside a custom
          callable, you must call the returned callable, for example:
  
          .. code-block:: python3
  
              async def get_prefix(bot, message):
                  extras = await prefixes_for(message.guild) # returns a list
                  return commands.when_mentioned_or(*extras)(bot, message)
  
  
      See Also
      ----------
      :func:`.when_mentioned`