try

tomli/_re.py

@@ -5,10 +5,6 @@
 
 from tomli._types import ParseFloat
 
-# Remove when support for Python 3.6 is dropped and use `re.Pattern` directly
-# https://github.com/python/cpython/blob/3.6/Lib/re.py#L283
-_re_pattern_type = getattr(re, "Pattern", None) or getattr(re, "_pattern_type", None)
-
 
 # E.g.
 # - 00:32:00.999999
@@ -17,7 +13,7 @@
 
 
 class _LazyPatternCompiler:
-    def __getattr__(self, name: str) -> _re_pattern_type:
+    def __getattr__(self, name: str) -> "re.Pattern":
         if name == "datetime":
             pattern = re.compile(
                 fr"""
@@ -58,7 +54,6 @@ def __getattr__(self, name: str) -> _re_pattern_type:
         setattr(self, name, pattern)
         return pattern
 
-
 Patterns = _LazyPatternCompiler()