Fix some typing errors in DuckArrayModule (#7296)

* Fix some typing errors in DuckArrayModule

* Update pycompat.py

* Update pycompat.py

xarray/core/pycompat.py

@@ -1,7 +1,8 @@
 from __future__ import annotations
 
 from importlib import import_module
-from typing import Any, Literal
+from types import ModuleType
+from typing import TYPE_CHECKING, Any, Literal, Type
 
 import numpy as np
 from packaging.version import Version
@@ -10,7 +11,9 @@
 
 integer_types = (int, np.integer)
 
-ModType = Literal["dask", "pint", "cupy", "sparse"]
+if TYPE_CHECKING:
+    ModType = Literal["dask", "pint", "cupy", "sparse"]
+    DuckArrayTypes = tuple[Type[Any], ...]  # TODO: improve this? maybe Generic
 
 
 class DuckArrayModule:
@@ -21,12 +24,15 @@ class DuckArrayModule:
     https://github.com/pydata/xarray/pull/5561#discussion_r664815718
     """
 
-    module: ModType | None
+    module: ModuleType | None
     version: Version
-    type: tuple[type[Any]]  # TODO: improve this? maybe Generic
+    type: DuckArrayTypes
     available: bool
 
     def __init__(self, mod: ModType) -> None:
+        duck_array_module: ModuleType | None = None
+        duck_array_version: Version
+        duck_array_type: DuckArrayTypes
         try:
             duck_array_module = import_module(mod)
             duck_array_version = Version(duck_array_module.__version__)
@@ -53,7 +59,7 @@ def __init__(self, mod: ModType) -> None:
         self.available = duck_array_module is not None
 
 
-def array_type(mod: ModType) -> tuple[type[Any]]:
+def array_type(mod: ModType) -> DuckArrayTypes:
     """Quick wrapper to get the array class of the module."""
     return DuckArrayModule(mod).type