Apply typing simplification changes from #512 to hdf filters. (#520)

Co-authored-by: Sean Harkins <[email protected]>

Author: sharkinsspatial

virtualizarr/readers/hdf/filters.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import dataclasses
 from typing import TYPE_CHECKING, List, Tuple, TypedDict, Union
 
@@ -9,17 +11,12 @@
 
 from virtualizarr.utils import soft_import
 
+h5py = soft_import("h5py", "For reading hdf files", strict=False)
+
+
 if TYPE_CHECKING:
-    import h5py  # type: ignore
-    from h5py import Dataset, Group  # type: ignore
+    from h5py import Dataset
 
-h5py = soft_import("h5py", "For reading hdf files", strict=False)
-if h5py:
-    Dataset = h5py.Dataset
-    Group = h5py.Group
-else:
-    Dataset = dict()
-    Group = dict()
 
 hdf5plugin = soft_import(
     "hdf5plugin", "For reading hdf files with filters", strict=False
@@ -28,7 +25,6 @@
     "imagecodecs", "For reading hdf files with filters", strict=False
 )
 
-
 _non_standard_filters = {
     "gzip": "zlib",
     "lzf": "imagecodecs_lzf",