mwparserfromhell is used by and originally developed for EarwigBot; Page objects have a parse() method that essentially calls mwparserfromhell.parse() on get().

If you’re using Pywikibot, your code might look like this:

import mwparserfromhell
import pywikibot

def parse(title):
    site = pywikibot.Site()
    page = pywikibot.Page(site, title)
    text = page.get()
    return mwparserfromhell.parse(text)

If you’re not using a library, you can parse any page using the following code (via the API):

import json
from urllib.parse import urlencode
from urllib.request import urlopen
import mwparserfromhell
API_URL = ""

def parse(title):
    data = {"action": "query", "prop": "revisions", "rvlimit": 1,
            "rvprop": "content", "format": "json", "titles": title}
    raw = urlopen(API_URL, urlencode(data).encode()).read()
    res = json.loads(raw)
    text = res["query"]["pages"].values()[0]["revisions"][0]["*"]
    return mwparserfromhell.parse(text)