diff --git a/src/flask/app.py b/src/flask/app.py
index ef475fda..352f095c 100644
--- a/src/flask/app.py
+++ b/src/flask/app.py
@@ -232,8 +232,7 @@ class Flask(App):
         host_matching: bool = False,
         subdomain_matching: bool = False,
         template_folder: (
-            str | os.PathLike[str] |
-            t.Sequence[t.Union[str, "os.PathLike[str]"]] | None
+            str | os.PathLike[str] | t.Sequence[str | os.PathLike[str]] | None
         ) = "templates",
         instance_path: str | None = None,
         instance_relative_config: bool = False,
diff --git a/src/flask/blueprints.py b/src/flask/blueprints.py
index 1fb1b987..dbccb08b 100644
--- a/src/flask/blueprints.py
+++ b/src/flask/blueprints.py
@@ -23,9 +23,8 @@ class Blueprint(SansioBlueprint):
         static_folder: str | os.PathLike[str] | None = None,
         static_url_path: str | None = None,
         template_folder: (
-            str | os.PathLike[str] | None |
-            t.Sequence[t.Union[str, "os.PathLike[str]"]] | None
-        )= None,
+            str | os.PathLike[str] | None | t.Sequence[str | os.PathLike[str]] | None
+        ) = None,
         url_prefix: str | None = None,
         subdomain: str | None = None,
         url_defaults: dict[str, t.Any] | None = None,
diff --git a/src/flask/sansio/app.py b/src/flask/sansio/app.py
index d378ea15..fdc730e2 100644
--- a/src/flask/sansio/app.py
+++ b/src/flask/sansio/app.py
@@ -288,8 +288,7 @@ class App(Scaffold):
         host_matching: bool = False,
         subdomain_matching: bool = False,
         template_folder: (
-            str | os.PathLike[str] |
-            t.Sequence[t.Union[str, "os.PathLike[str]"]] | None
+            str | os.PathLike[str] | t.Sequence[str | os.PathLike[str]] | None
         ) = "templates",
         instance_path: str | None = None,
         instance_relative_config: bool = False,
diff --git a/src/flask/sansio/blueprints.py b/src/flask/sansio/blueprints.py
index 5e7b43c3..517f7ee9 100644
--- a/src/flask/sansio/blueprints.py
+++ b/src/flask/sansio/blueprints.py
@@ -179,8 +179,7 @@ class Blueprint(Scaffold):
         static_folder: str | os.PathLike[str] | None = None,
         static_url_path: str | None = None,
         template_folder: (
-            str | os.PathLike[str] |
-            t.Sequence[t.Union[str, "os.PathLike[str]"]] | None
+            str | os.PathLike[str] | t.Sequence[str | os.PathLike[str]] | None
         ) = None,
         url_prefix: str | None = None,
         subdomain: str | None = None,
diff --git a/src/flask/sansio/scaffold.py b/src/flask/sansio/scaffold.py
index 6c62840a..e2d5e1f0 100644
--- a/src/flask/sansio/scaffold.py
+++ b/src/flask/sansio/scaffold.py
@@ -6,7 +6,6 @@ import pathlib
 import sys
 import typing as t
 from collections import defaultdict
-from collections.abc import Sequence
 from functools import update_wrapper
 
 from jinja2 import BaseLoader
@@ -79,8 +78,7 @@ class Scaffold:
         static_folder: str | os.PathLike[str] | None = None,
         static_url_path: str | None = None,
         template_folder: (
-            str | os.PathLike[str] |
-            t.Sequence[t.Union[str, "os.PathLike[str]"]] | None
+            str | os.PathLike[str] | t.Sequence[str | os.PathLike[str]] | None
         ) = None,
         root_path: str | None = None,
     ):
@@ -284,14 +282,15 @@ class Scaffold:
         if self.template_folder is None:
             return None
         if isinstance(self.template_folder, str):
-            return FileSystemLoader(
-                os.path.join(self.root_path, self.template_folder)
-            )
-        return FileSystemLoader([
-            folder if isinstance(folder, os.PathLike)
-            else os.path.join(self.root_path, folder)
-            for folder in self.template_folder
-        ])
+            return FileSystemLoader(os.path.join(self.root_path, self.template_folder))
+        return FileSystemLoader(
+            [
+                folder
+                if isinstance(folder, os.PathLike)
+                else os.path.join(self.root_path, folder)
+                for folder in self.template_folder
+            ]
+        )
 
     def _method_route(
         self,