@commands.command(aliases=['rtd'], description='usage: roll, roll 2, roll 8d12, roll 5d20+8')
    async def roll(self, ctx, adxopb=None):
        '''(rtd) Rolls dice in AdX+B notation. Default 1d6+0'''
        adxopb = adxopb.lower()
        op, b, opb = '', 0, ''

        if adxopb is None:
            adx = adxopb = '1d6'
        elif adxopb.isdigit():             # if no 'd':
            adx = adxopb = f'{adxopb}d6'   #   default all d6
        elif '+' in adxopb:
            adx, op, b = adxopb.partition('+')
            opb = f'{op}{b}'
        elif '-' in adxopb:
            adx, op, b = adxopb.partition('-')
            opb = f'{op}{b}'
        else:
            adx = adxopb

        try:
            a, x = map(int, adx.split('d'))             # extract numbers
            rolls = [random.randrange(1, x+1) for die in range(a)]
            total = self.ops[op](sum(rolls), int(b))    # sum of all rolls +/- b
        except ValueError as e:
            await ctx.send(f":interrobang: Invalid input: `{adxopb}`. Only `0-9 d + -` allowed.")
        else:
            rolls = ' '.join(list(map(str, rolls)))
            output = f"🎲 **{total}**   |   *{ctx.author.display_name} rolled {adxopb.lower()}* ```x1\n{rolls} ({opb})```"
            await ctx.message.delete()
            await ctx.send(output)