Retrieves the bot mapping passed to :meth:`send_bot_help`.

def get_bot_mapping(self):
        """Retrieves the bot mapping passed to :meth:`send_bot_help`."""
        bot = self.context.bot
        mapping = {
            cog: cog.get_commands()
            for cog in bot.cogs.values()
        }
        mapping[None] = [c for c in bot.all_commands.values() if c.cog is None]
        return mapping