Reduce import time part 2: lazy import rarely used datetime

src/tomli/_re.py

@@ -4,12 +4,13 @@
 
 from __future__ import annotations
 
-from datetime import date, datetime, time, timedelta, timezone, tzinfo
 from functools import lru_cache
 import re
 from typing import TYPE_CHECKING, Any, Final
 
 if TYPE_CHECKING:
+    from datetime import date, datetime, time, timezone
+
     from ._types import ParseFloat
 
 # E.g.
@@ -58,6 +59,8 @@ def match_to_datetime(match: re.Match) -> datetime | date:
     Raises ValueError if the match does not correspond to a valid date
     or datetime.
     """
+    from datetime import date, datetime, timezone, tzinfo
+
     (
         year_str,
         month_str,
@@ -92,6 +95,8 @@ def match_to_datetime(match: re.Match) -> datetime | date:
 # 24 (hours) * 60 (minutes) * 2 (offset direction) = 2880.
 @lru_cache(maxsize=None)
 def cached_tz(hour_str: str, minute_str: str, sign_str: str) -> timezone:
+    from datetime import timedelta, timezone
+
     sign = 1 if sign_str == "+" else -1
     return timezone(
         timedelta(
@@ -102,6 +107,8 @@ def cached_tz(hour_str: str, minute_str: str, sign_str: str) -> timezone:
 
 
 def match_to_localtime(match: re.Match) -> time:
+    from datetime import time
+
     hour_str, minute_str, sec_str, micros_str = match.groups()
     micros = int(micros_str.ljust(6, "0")) if micros_str else 0
     return time(int(hour_str), int(minute_str), int(sec_str), micros)