diff --git a/law/parameter.py b/law/parameter.py
index ac51863f..57fd7a77 100644
--- a/law/parameter.py
+++ b/law/parameter.py
@@ -387,7 +387,7 @@ def _check_sort(self, value: tuple[T]) -> tuple[T]:
             return value
 
         key = self._sort if callable(self._sort) else None
-        return tuple(sorted(value, key=key))  # type: ignore[return-value]
+        return tuple(sorted(value, key=key))  # type: ignore[return-value, type-var]
 
     def _check_len(self, value: tuple[Any]) -> None:
         str_repr = lambda: ",".join(str(v) for v in value)
diff --git a/law/target/file.py b/law/target/file.py
index 2248f5a6..6c802315 100644
--- a/law/target/file.py
+++ b/law/target/file.py
@@ -208,6 +208,7 @@ def move(  # type: ignore[override]
         ...
 
     @abstractmethod
+    @contextlib.contextmanager
     def open(
         self,
         path: str | pathlib.Path,
@@ -216,7 +217,7 @@ def open(
         perm: int | None = None,
         dir_perm: int | None = None,
         **kwargs,
-    ) -> AbstractContextManager[IO]:
+    ) -> Iterator[IO]:
         ...
 
 
@@ -441,7 +442,7 @@ def localize(
         dir_perm: int | None = None,
         tmp_dir: str | pathlib.Path | None = None,
         **kwargs,
-    ) -> Generator[FileSystemTarget, None, None]:
+    ) -> Iterator[FileSystemTarget]:
         ...
 
     @abstractmethod
diff --git a/law/target/local.py b/law/target/local.py
index 1c9ef7fb..24fa73ba 100644
--- a/law/target/local.py
+++ b/law/target/local.py
@@ -363,7 +363,7 @@ def move(  # type: ignore[override]
 
         return dst
 
-    def open(
+    def open(  # type: ignore[override]
         self,
         path: str | pathlib.Path,
         mode: str,
diff --git a/law/target/mirrored.py b/law/target/mirrored.py
index a0a70e52..bbadac74 100644
--- a/law/target/mirrored.py
+++ b/law/target/mirrored.py
@@ -22,7 +22,7 @@
     RemoteFileSystem, RemoteTarget, RemoteFileTarget, RemoteDirectoryTarget,
 )
 from law.util import patch_object
-from law._types import Any, Type, Generator, AbstractContextManager, IO, Iterator
+from law._types import Any, Type, Generator, Iterator, IO
 
 
 local_root_check_lock = threading.Lock()
@@ -295,7 +295,7 @@ def move_from_local(self, *args, **kwargs) -> str:
         return ret
 
     @contextlib.contextmanager
-    def localize(self, mode: str = "r", **kwargs) -> Generator[FileSystemTarget, None, None]:
+    def localize(self, mode: str = "r", **kwargs) -> Iterator[FileSystemTarget]:
         with (
             self.local_target.localize(mode=mode, **kwargs)
             if (mode == "r" or not self.local_read_only) and self._local_target_exists()
@@ -336,12 +336,14 @@ class MirroredFileTarget(FileSystemFileTarget, MirroredTarget):
     def __init__(self, path: str | pathlib.Path, **kwargs) -> None:
         super().__init__(path, _is_file=True, **kwargs)
 
-    def open(self, mode: str, **kwargs) -> AbstractContextManager[IO]:
-        ret = (
+    @contextlib.contextmanager
+    def open(self, mode: str, **kwargs) -> Iterator[IO]:
+        with (
             self.local_target.open(mode, **kwargs)
             if (mode == "r" or not self.local_read_only) and self._local_target_exists()
             else self.remote_target.open(mode, **kwargs)
-        )
+        ) as ret:
+            yield ret
         if mode == "w" and self.local_read_only and self.local_sync:
             self._wait_for_local(missing=False)
         return ret
diff --git a/pyproject.toml b/pyproject.toml
index 964dcf3b..2a3eb714 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -88,4 +88,4 @@ exclude = ["tests/*"]
 [tool.mypy]
 
 disable_error_code = ["no-redef", "valid-type", "method-assign"]
-exclude = ["law/templates/*", "docs", "examples", "tests", "build"]
+exclude = ["law/templates/*", "docs", "examples", "tests", "build", "setup.py"]
diff --git a/requirements_dev.txt b/requirements_dev.txt
index cb3ad191..477e1b5a 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -1,4 +1,4 @@
-mypy~=1.11.1;python_version>="3.8"
+mypy~=1.13.0;python_version>="3.8"
 flake8~=7.1.1;python_version>="3.8"
 flake8~=5.0.0;python_version<"3.8"
 flake8-commas~=2.1.0;python_version<"3.8"