docs: async def _default_help_command(ctx, *commands : str):
      """Shows this message."""
      bot = ctx.bot
      destination = ctx.message.author if bot.pm_help else ctx.message.channel
  
      def repl(obj):
          return _mentions_transforms.get(obj.group(0), '')
  
      # help by itself just lists our own commands.
      if len(commands) == 0:
          pages = bot.formatter.format_help_for(ctx, bot)
      elif len(commands) == 1:
          # try to see if it is a cog name
          name = _mention_pattern.sub(repl, commands[0])
          command = None
          if name in [x.lower() for x in bot.cogs]:
              command = bot.cogs[[x for x in bot.cogs if x.lower() == name][0]]
          else:
              command = bot.commands.get(name)
              if command is None:
                  await bot.responses.failure(destination=destination, message=bot.command_not_found.format(name))
                  return
  
          pages = bot.formatter.format_help_for(ctx, command)
      else:
          name = _mention_pattern.sub(repl, commands[0])
          command = bot.commands.get(name)
          if command is None:
              await bot.responses.failure(destination=destination, message=bot.command_not_found.format(name))
              return
  
          for key in commands[1:]:
              try:
                  key = _mention_pattern.sub(repl, key)
                  command = command.commands.get(key)
                  if command is None:
                      await bot.responses.failure(destination=destination, message=bot.command_not_found.format(name))
                      return
              except AttributeError:
                  await bot.responses.failure(destination=destination, message=bot.command_has_no_subcommands.format(command, key))
                  return
  
          pages = bot.formatter.format_help_for(ctx, command)
  
      if bot.pm_help is None:
          characters = sum(map(lambda l: len(l), pages.values()))
          if characters > 1000:
              destination = ctx.message.author
  
      await bot.responses.full(destination=destination, **pages)