import re

UPDATE_REGEX = r"<UpdateField Id=\"\w+\" Group=\"\w+\" UIRequired=\"\d+\" UIDisabled=\"\d+\" ForceUpdate=\"\d+\">\n((?!</U)(.|\n))*</Up"




ms = re.finditer(UPDATE_REGEX, S2)
for m in ms:
    print(m.group())
    idMatch = re.search(r"\"\w+\"",m.group())
    print(idMatch)