检查此：https://www.w3schools.com/python/gloss_python_function_default_parameter.asp
您也可以使用None作为默认参数，并以其他方式处理它：

@bee.command(name="돈얼마", description="지갑 지갑을 보자!")
async def 돈얼마(interaction: discord.Interaction, 멘션: discord.User = None):
    if 멘션 is not None:
        userid = 멘션.id
        embed=discord.Embed(title="돈 지급", description=f"잔액 : {money[userid]}원\n" + f"이정도 밖에 없는건 아니죠? 에이", color=0x5cff67)
        await interaction.response.send_message(embed=embed)
    else:
        foo() # replace with code to execute when 멘션 is not given

当给出时，它将像往常一样执行，否则将执行foo()。