rut.py

import requests


url = 'https://chile.rutificador.com/'

client = requests.session()
client.get(url)
csrftoken = client.cookies['csrftoken']

url = url + 'get_generic_ajax/'

data = {
    'entrada': 'Pedro',
    'csrfmiddlewaretoken': csrftoken,
}

headers = {
    'Referer': url,
}

response = client.post(url, data=data, headers=headers)

response.json()