how to mention the user that send the message discord.py code example

Example 1: discord.py message user

if message.content == "dm":
        await message.channel.send("Dming user")
        dm = await message.author.create_dm()  # Creates a dm channel with the user
        await dm.send("What you want to send")  # Sends the user the message

Example 2: how to mention someone discord.py

myid = '<@201909896357216256>'
await client.send_message(message.channel, ' : %s is the best ' % myid)