function to kill whatever is running on port 8000 and start `runserver_plus` using port 8000

django_runserver_plus.sh

#!/usr/bin/env bash

function start_runserver_plus() {
    cd /path/to/project/dir && workon myvenv && python manage.py runserver_plus 0.0.0.0:8000 --traceback -v 3 --threaded
}

function rs() {
    # lsof -i :8000 lists processes using the 8000 port, -t option returns only the process ID
    d_pid=`lsof -t -i :8000`
    if [[ $d_pid ]]; then
        echo "something is using 8000... Killing it!"
        kill -9 $d_pid
        echo "starting server..."
        start_runserver_plus
    else
        echo "nothing to kill... starting server..."
        start_runserver_plus
    fi
}
rs

how do i run it please.