def extract_data(page):
    data = {"eventvalidation": "",
            "viewstate": ""}
    with open(page, "r") as html:
        # do something here to find the necessary values
        soup = BeautifulSoup(html, "lxml")
        ev = soup.find(id="__EVENTVALIDATION")
        data["eventvalidation"] = ev["value"]

        vs = soup.find(id="__VIEWSTATE")
        data["viewstate"] = vs["value"]

    return data

