conversations_history.py

import requests as rq
import pandas as pd

msg_url = 'https://slack.com/api/conversations.history'
msg_headers = {'content-type': 'application/x-www-form-urlencoded'}
msg_params = {
    'token': 'xoxp-XXXXXXXXXXXX-XXXXXXXXXXXX-XXXXXXXXXXXXX-XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX',
    'channel': 'CXXXXXXXX',
    'limit': 1000
}

msg_res = rq.get(url=msg_url, headers=msg_headers, params=msg_params)
msg = [i['ts'] for i in msg_res.json()['messages']]