Python discord.ext.commands 模块，CommandError() 实例源码

def skip(self, ctx, force: str = None):
        # if the skip is forced, check the privilege and do it
        if force and force.lower() in ['f', 'force']:
            if not self._bot.is_operator(ctx.message.author):
                raise dec.CommandError('You don\'t have a permission to force the skip')
            await self._bot.player.force_skip()
            await self._bot.message('Skip forced by {}'.format(ctx.message.author.mention))
            return

        # if the argument is not none, raise an error
        if force is not None:
            raise dec.UserInputError('*force* is the only argument allowed for the *skip* command')

        # now do the "normal voting"
        await self._bot.player.skip_vote(int(ctx.message.author.id))
        await self._bot.log('User {} has voted to skip'.format(ctx.message.author))

def member_by_substring(ctx: commands.Context, substring: str):
    """This searches for a member by substrings."""
    try:
        return await memberconverter.convert(ctx, substring)
    except commands.CommandError:
        pass
    substring = substring.lower()
    for member in ctx.guild.members:
        if substring in member.name.lower() or substring in member.display_name.lower():
            return member
    raise commands.BadArgument(f"No user with substring `{substring}` was found.")

def role_by_substring(ctx: commands.Context, substring: str):
    """This searches for a role by substrings."""
    try:
        return await roleconverter.convert(ctx, substring)
    except commands.CommandError:
        pass
    substring = substring.lower()
    for role in ctx.guild.roles:
        if substring in role.name.lower():
            return role
    raise commands.BadArgument(f"No role with substring `{substring}` was found.")

def _can_run(command, ctx):
    try:
        return await command.can_run(ctx)
    except commands.CommandError:
        return False

def _command_check(self, ctx):
        # if the channel is not private, delete the command immediately regardless of the response
        if not isinstance(ctx.message.channel, discord.PrivateChannel):
            self._bot.loop.create_task(self._bot.client.delete_message(ctx.message))

        # if privileged, check the member role
        if hasattr(ctx.command, 'privileged'):
            if not self._bot.is_operator(ctx.message.author):
                raise dec.CommandError('You don\'t have a permission to use the *{}* command'.format(ctx.command))

        return True

    #
    # Listeners
    #

def role_or_permissions(ctx, check, **perms):
    if check_permissions(ctx, perms):
        return True

    ch = ctx.message.channel
    author = ctx.message.author
    if isinstance(ch, (discord.DMChannel, discord.GroupChannel)):
        return False  # can't have roles in PMs

    role = discord.utils.find(check, author.roles)
    if role is None:
        raise commands.CommandError("You need a special role to do this! (A discord role with the name \"Bot Mod\" or \"Bot Admin\")")
    return True

def filter_command_list(self, command):
        """Returns a filtered list of commands based on the two attributes
        provided, :attr:`show_check_failure` and :attr:`show_hidden`. Also
        filters based on if :meth:`is_cog` is valid.
        Returns
        --------
        iterable
            An iterable with the filter being applied. The resulting value is
            a (key, value) tuple of the command name and the command itself.
        """

        def sane_no_suspension_point_predicate(tup):
            cmd = tup[1]
            if self.is_cog(command):
                # filter commands that don't exist to this cog.
                if cmd.instance is not command:
                    return False

            if cmd.hidden and not self.show_hidden:
                return False

            return True

        async def predicate(tup):
            if sane_no_suspension_point_predicate(tup) is False:
                return False

            cmd = tup[1]
            try:
                return await cmd.can_run(self.context)
            except commands.CommandError:
                return False

        iterator = command.all_commands.items() if not self.is_cog(command) else self.context.bot.all_commands.items()
        if self.show_check_failure:
            return filter(sane_no_suspension_point_predicate, iterator)

        # Gotta run every check and verify it
        ret = []
        for elem in iterator:
            valid = await predicate(elem)
            if valid:
                ret.append(elem)

        return ret