Use python 3.12 type syntax

Author: maxnoe

docs/conf.py

@@ -134,6 +134,7 @@ def add_reference_type(prefix, objs):
         "Sentinel",
         "ObserveHandler",
         "dict[K, V]",
+        "T",
         "G",
         "K",
         "V",
@@ -144,11 +145,8 @@ def add_reference_type(prefix, objs):
         "astropy.coordinates.baseframe.BaseCoordinateFrame",
         "astropy.table.table.Table",
         "eventio.simtel.simtelfile.SimTelFile",
-        "ctapipe.core.container.T",
         "ctapipe.core.container.T1",
         "ctapipe.core.container.T2",
-        "ctapipe.core.container.K",
-        "ctapipe.core.container.V",
         "DTypeLike",
     ],
 )
@@ -167,11 +165,9 @@ def add_reference_type(prefix, objs):
         "-v",  # fix for wrong syntax in a traitlets docstring
         "cls",
         "name",
-        "ctapipe.core.container.T",
+        "T",
         "ctapipe.core.container.T1",
         "ctapipe.core.container.T2",
-        "ctapipe.core.container.K",
-        "ctapipe.core.container.V",
     ],
 )
 nitpick_ignore += add_reference_type(

src/ctapipe/core/container.py

@@ -5,7 +5,7 @@
 from inspect import isclass
 from pprint import pformat
 from textwrap import dedent, wrap
-from typing import Any, Callable, Generic, Self, Type, TypeVar, overload
+from typing import Any, Callable, Self, Type, TypeVar, overload
 
 import numpy as np
 from astropy.units import Quantity, Unit, UnitBase, UnitConversionError
@@ -24,12 +24,11 @@ class FieldValidationError(ValueError):
     pass
 
 
-T = TypeVar("T")
 T1 = TypeVar("T1")
 T2 = TypeVar("T2")
 
 
-class Field(Generic[T]):
+class Field[T]:
     """
     Class for storing data in a `Container`.
 
@@ -178,11 +177,11 @@ def __init__(
     # we only specify the Descriptor protocol __get__ here has it helps type checkers
     # and IDEs to provide insights on types of container fields. It is not actually used at runtime
     # since the ContainerMeta turns Fields into __slots__ based access to member variables.
-    # 2. When accessed via the class (e.g., MyContainer.foo), only owner present
+    # 1. When accessed via the class (e.g., MyContainer.foo), only owner present
     @overload
     def __get__(self, instance: None, owner: Any) -> Self: ...
 
-    # 1. access via instance, both arguments present
+    # 2. access via instance, both arguments present
     @overload
     def __get__(self, instance: "Container", owner: "Type[Container]") -> T: ...
 
@@ -567,11 +566,7 @@ def validate(self):
                 )
 
 
-K = TypeVar("K")
-V = TypeVar("V")
-
-
-class Map(defaultdict[K, V]):
+class Map[K, V](defaultdict[K, V]):
     """A dictionary of sub-containers that can be added to a Container. This
     may be used e.g. to store a set of identical sub-Containers (e.g. indexed
     by ``tel_id`` or algorithm name).