study.py

import requests

cookies = {
    'csrftoken': 'oMf6Oy9UmwlpCtveOB3bo4S1aU0t5Mv5n6HSyxx0NhF9D7AiQG9ORerg3QIJTz84',
    'sessionid': '4w8ipimaz3h57dpr19693xe5juvtmkck',
}

headers = {
    'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:89.0) Gecko/20100101 Firefox/89.0',
    'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8',
    'Accept-Language': 'en-US,en;q=0.5',
    'Referer': 'https://www.studyup.xyz/s/group/35',
    'Content-Type': 'application/x-www-form-urlencoded',
    'Origin': 'https://www.studyup.xyz',
    'DNT': '1',
    'Connection': 'keep-alive',
    'Upgrade-Insecure-Requests': '1',
    'Sec-Fetch-Dest': 'document',
    'Sec-Fetch-Mode': 'navigate',
    'Sec-Fetch-Site': 'same-origin',
    'Sec-Fetch-User': '?1',
    'Pragma': 'no-cache',
    'Cache-Control': 'no-cache',
}

with open('anna.txt', 'r') as f:
    anna = f.read()

data = {
  'csrfmiddlewaretoken': 'kgtCqOKeQBJJOlUE63JBJS0qIBwBhzhajAVoaN8khm3tPZZI88Pec2zFBxeR5mU9',
  'contents': 'Testing message. Here\'s Anna Karenina by Leo Tolstoy: ' + anna,
  'form_name': 'comment'
}

response = requests.post('https://www.studyup.xyz/s/put_comment/35', headers=headers, cookies=cookies, data=data)
print(response.text)