I need help about my discord bot but there is an error anyone can help me?

I wrote some codes about my discord bot but only my avatar command is not working anyone can help me ? There is my code

@Bot.command()
async def avatar(ctx,member : discord.Member=None):
    if member == None:
        member = ctx.author
    memberAvatar = member.avatar_url

    avaEmbed = discord.embed(title = f"(member.name)'in avatarı")
    avaEmbed.set_image(url = memberAvatar)

    await channel.send(embed = avaEmbed)