discord py delete own message

1@client.event
2async def on_message(message):
3    await message.delete()

1msg = await ctx.send("This is a message")
2await msg.delete()

1await ctx.send("This is a message", delete_after=5) # deletes message after 5 seconds

1@client.command()
2async def _clear(ctx,amount=1):
3  await ctx.channel.purge(limit=amount+1)