How does posting work with `requests` in python?

Question

For this example specifically, I'm trying to make it so that I can automatically scrape the direct stream url from here which can be found in the video iframe this (iframe["src"])

The default server when first entering the webpage is "server40", or VidStream but in order to get the working url, I need the src from the video iframe from Streamtape but in order to switch servers, you are required to click on the desired server. In my case, I want to click on Streamtape when I enter the website, but that requires posting a requests or whatever which I am not familiar with.

I've spent awhile messing around with it all using HTMLSession from requests_html but haven't gotten very far.

I have gotten to the point where I found the key for the post requests which I found by going into the Network tab in Firefox and looking under requests for the Post request.

This is what I have so far:

from requests_html import HTMLSession
from bs4 import BeautifulSoup
from requests import get


def grabpost(ld, new={}):  # Create dict then grab key from 'server40'
    [new.update({x[0]:x[1]}) for x in ld]; return new.get("40")

def grabhtml(session, url):  # Auto requests_html for html/js only
    res = session.get(url); res.html.render(); session.close(); return res


AJAX = "https://www12.9anime.to/ajax/user/watching"
URL = "https://www12.9anime.to/watch/descending-stories-showa-genroku-rakugo-shinju.xojv/ep-2"

headers = {"content-type": "application/json"}

TYPE = URL.rsplit(".")[-1].split("/")[0]



###  Grab key for 'Streamtape' server [server40]

s1 = HTMLSession()

soup = BeautifulSoup(grabhtml(s1, URL).html.html, "lxml")

servers = soup.find("a", class_="active")["data-sources"].replace('"', "")[1:-1].split(",")

KEY = grabpost([x.split(":") for x in servers])

data = {TYPE:KEY}



### Post onto AJAX then grab URL during s2

s2 = HTMLSession()

post = s2.post(url=AJAX, data=data, headers=headers)

res = grabhtml(s2, URL)

soup = BeautifulSoup(res.html.html, "lxml")


GOAL = soup.find("iframe")["src"].split("?")[0]  # Should be "https://streamtape.com/e/QJ07RkJ0JDU0zZ4/"

# if GOAL is "https://vidstream.pro/e/ZLPG4V426Y7X", then the post didn't work and is still on "VidStream"



print(GOAL)