hey im making a giveaway command but it throws a error “‘async_generator’ object has no attribute ‘flatten'”

so im making a giveaway command for my bot in discord.py v2 but it throws this error: ‘async_generator’ object has no attribute ‘flatten’

here is an image:

my code –

@client.command(description="Starts a giveaway.")
@has_permissions(manage_messages=True)
async def gcreate(ctx, mins: int, *, prize: str):
    global users, new_msg
    try:
        em = discord.Embed(
            title=f"<a:fun:1052215771738165269> {prize} <a:fun:1052215771738165269>",
            color=discord.Colour.random()
        )
        # end = datetime.datetime.utcnow() + datetime.timedelta(seconds=mins *60)
        timestamp = time.time() + mins
        em.set_footer(text=f"Started by {ctx.author}")
        em.add_field(name=f"** **", value=f"**Ends at**: <t:{int(timestamp)}:f> or <t:{int(timestamp)}:R> n **Prize**: {prize} n **Hosted by**: {ctx.author.mention}", inline=False)
        my_msg = await ctx.send(embed=em)
        await my_msg.add_reaction("🎉")
        await asyncio.sleep(mins)
        new_msg = await ctx.channel.fetch_message(my_msg.id)
        users = await new_msg.reactions[0].users().flatten()
        users.pop(users.index(client.user))
        winner = random.choice(users)
        await ctx.send(f'Congratulations {winner.mention} won **{prize}**! Hosted by {ctx.author.mention}')
        em = discord.Embed(
            title=f"Hey! you won **{prize} GG**!",
            description="Join the dev's server https://discord.gg/notsetyet <:",
            color=0xff2424
        )
        em.set_author(name=winner.name, icon_url=winner.avatar_url)
        await winner.send(embed=em)
    except Exception as er:
        await ctx.send(er)

@client.command(description="Rerolls the recent giveaway.")
@has_permissions(manage_messages=True)
async def reroll(ctx, channel: discord.TextChannel, id):
    try:
        new_message = await channel.fetch_message(id)
    except:
        await ctx.send("Incorrect id.")
        return

    users = await new_message.reactions[0].users().flatten()
    users.pop(users.index(client.user))
    winner = random.choice(users)

    reroll_announcement = discord.Embed(color = 0xff2424)
    reroll_announcement.set_author(name = f'The giveaway was re-rolled by the host!', icon_url = 'https://i.imgur.com/DDric14.png')
    reroll_announcement.add_field(name = f'🥳 New Winner:', value = f'{winner.mention}', inline = False)
    await channel.send(embed = reroll_announcement)

i know that flatten has been removed in discord.py v2 but i dont know how to implement the new one im confused any type of help will be appreciated!

Answer

The discord.Reaction.users were changed to return an async generator (PEP 525) and have to be turned into a list in your use case. You can easily do it using list comprehension like:

users = [user async for user in reaction.users()]

Instead of:

users = await new_msg.reactions[0].users().flatten()

The example of this can be found in discord.py discord.Reaction.users document.