Exercise 2 solution

    import re
    log = """2026-11-02 ERROR disk full
    2026-11-02 info started
    2026-11-03 Warn cpu high
    2026-11-03 debug noise"""

    pat = r"^(?P<date>\d{4}-\d{2}-\d{2}) (?P<level>error|warn)\s+(?P<msg>.*)$"

    for m in re.finditer(pat, log, re.I | re.M):
        print(m.groupdict())
    # {'date': '2026-11-02', 'level': 'ERROR', 'msg': 'disk full'}
    # {'date': '2026-11-03', 'level': 'Warn', 'msg': 'cpu high'}

    print(re.findall(pat, log))     # []

(In the script, the log lines must start at the left margin of the string,
 not indented, or ^ will not line up; the output above is from the
 unindented version, which was run.)

Explanation: re.M lets ^ and $ match at each line, and re.I lets "ERROR" and
"Warn" match the lower-case words in the pattern. Without the flags, ^ can
only match at the start of the whole string and $ only at its end, and the
level words are case-sensitive, so no match is possible and findall returns
an empty list.