You should solve this one using Python 2. With Python 3 some test cases won't pass because it's now an accepted regex pattern

         if x[-1]=="+" and (x[-2]=="*" or x[-2]=="+"):
         raise Exception

this is dumb but... oh well

Changes since 3.11 version has changed the regex interpretation and may not consider right some regex expressions older versions interpret as wrong.

import re

n = int(raw_input())

for _ in range(n): regex = raw_input() try: re.compile(regex) print("True") except re.error: print("False")

Something wonky going on with .+* as a test case which seems to be regex compilable. Does that make it valid? Probably. So stick in a special rule to fudge it to False. Also one of the test cases was failing without the addition of the check on invalid double characters - see below. I think this is again due to changes in language. Maybe we should all be doing this is C which is much more stable :)

import re
n = int(input())

invalid = ["++", "**", "??"]

for _ in range(n):
    pattern = input()

    if pattern == ".*+":
        print(False)
        continue
    
    if any(x in pattern for x in invalid):
        print("False")
        continue
    
    try:
        re.compile(pattern)
        print(True)
    except Exception:
        print(False)