From a088f5d22bcd8a9761353d3e500403daa42df33f Mon Sep 17 00:00:00 2001
From: Vasista Vovveti <vasistavovveti@gmail.com>
Date: Thu, 18 Jan 2024 01:55:03 -0800
Subject: [PATCH] Fix typing of deprecated aliases (#44)

---
 commands2/__init__.py  | 25 +++++++++++++++----------
 commands2/subsystem.py |  3 ++-
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/commands2/__init__.py b/commands2/__init__.py
index 4d9c2e8c..18b310d7 100644
--- a/commands2/__init__.py
+++ b/commands2/__init__.py
@@ -48,6 +48,8 @@
 from .waituntilcommand import WaitUntilCommand
 from .wrappercommand import WrapperCommand
 
+from typing import TYPE_CHECKING
+
 __all__ = [
     "cmd",
     "Command",
@@ -98,18 +100,21 @@
     "Trigger",  # was here in 2023
 ]
 
+if not TYPE_CHECKING:
 
-def __getattr__(attr):
-    if attr == "SubsystemBase":
-        import warnings
+    def __getattr__(attr):
+        if attr == "SubsystemBase":
+            import warnings
 
-        warnings.warn("SubsystemBase is deprecated", DeprecationWarning, stacklevel=2)
-        return Subsystem
+            warnings.warn(
+                "SubsystemBase is deprecated", DeprecationWarning, stacklevel=2
+            )
+            return Subsystem
 
-    if attr == "CommandBase":
-        import warnings
+        if attr == "CommandBase":
+            import warnings
 
-        warnings.warn("CommandBase is deprecated", DeprecationWarning, stacklevel=2)
-        return Command
+            warnings.warn("CommandBase is deprecated", DeprecationWarning, stacklevel=2)
+            return Command
 
-    raise AttributeError("module {!r} has no attribute " "{!r}".format(__name__, attr))
+        raise AttributeError(f"module {__name__!r} has no attribute {attr!r}")
diff --git a/commands2/subsystem.py b/commands2/subsystem.py
index a3ba81ca..56724ebd 100644
--- a/commands2/subsystem.py
+++ b/commands2/subsystem.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 from typing import TYPE_CHECKING, Callable, Optional
+from typing_extensions import Self
 
 if TYPE_CHECKING:
     from .command import Command
@@ -28,7 +29,7 @@ class Subsystem(Sendable):
     base for user implementations that handles this.
     """
 
-    def __new__(cls, *arg, **kwargs) -> "Subsystem":
+    def __new__(cls, *arg, **kwargs) -> Self:
         instance = super().__new__(cls)
         super().__init__(instance)
         SendableRegistry.addLW(instance, cls.__name__, cls.__name__)