Send private message to Discord user using bash and linux AT command

Question

I'm running a Discord bot written in Python nohup python3 ./bot.py &. With this bot you can schedule a task which has to run only once. I'm executing bash from Python to schedule a script to run at a certain time. This works.

I want to send the user a private message in Discord that the command has been executed. I can't think a way how to send the user a private message after the bash command has been executed. I know the username of the user because its part of the scheduled job.

My question: what is the best way to send a user a message using bash? If possible..