Add type hints to dicts

Add type hints to dicts to make mypy happy.

Author: bdrung

src/croniter/croniter.py

@@ -11,6 +11,7 @@
 import sys
 import traceback as _traceback
 from time import time
+from typing import Optional, Union
 
 from dateutil.relativedelta import relativedelta
 from dateutil.tz import tzutc
@@ -59,12 +60,12 @@ def is_32bit():
 EPOCH = datetime.datetime.fromtimestamp(0, UTC_DT)
 
 # fmt: off
-M_ALPHAS = {
+M_ALPHAS: dict[str, Union[int, str]] = {
     "jan": 1, "feb": 2,  "mar": 3,  "apr": 4,  # noqa: E241
     "may": 5, "jun": 6,  "jul": 7,  "aug": 8,  # noqa: E241
     "sep": 9, "oct": 10, "nov": 11, "dec": 12,
 }
-DOW_ALPHAS = {
+DOW_ALPHAS: dict[str, Union[int, str]] = {
     "sun": 0, "mon": 1, "tue": 2, "wed": 3, "thu": 4, "fri": 5, "sat": 6
 }
 
@@ -109,8 +110,8 @@ def is_32bit():
 YEAR_CRON_LEN = len(YEAR_FIELDS)
 # retrocompat
 VALID_LEN_EXPRESSION = {a for a in CRON_FIELDS if isinstance(a, int)}
-TIMESTAMP_TO_DT_CACHE = {}
-EXPRESSIONS = {}
+TIMESTAMP_TO_DT_CACHE: dict[int, datetime.datetime] = {}
+EXPRESSIONS: dict[tuple[str, Optional[bytes], bool], list[str]] = {}
 MARKER = object()
 
 
@@ -176,7 +177,7 @@ class croniter:
         (1970, 2099),
     )
 
-    ALPHACONV = (
+    ALPHACONV: tuple[dict[str, Union[int, str]], ...] = (
         {},  # 0: min
         {},  # 1: hour
         {"l": "l"},  # 2: dom
@@ -190,7 +191,7 @@ class croniter:
         {},
     )
 
-    LOWMAP = (
+    LOWMAP: tuple[dict[int, int], ...] = (
         {},
         {},
         {0: 1},

src/croniter/tests/base.py

@@ -7,4 +7,4 @@ class TestCase(unittest.TestCase):
     If necessary, we can put common utility or setup code in here.
     """
 
-    maxDiff = 10**10
+    maxDiff: int | None = 10**10