Apply ruff/flake8-type-checking rule TCH003 (pydicom#2103)

TCH003 Move standard library import into a type-checking block

src/pydicom/filebase.py

@@ -1,12 +1,14 @@
 # Copyright 2008-2020 pydicom authors. See LICENSE file for details.
 """Hold DicomFile class, which does basic I/O for a dicom file."""
 
-from collections.abc import Callable
 from io import BytesIO
 import os
 from struct import Struct
 from types import TracebackType
-from typing import cast, Any, TypeVar, Protocol
+from typing import TYPE_CHECKING, cast, Any, TypeVar, Protocol
+
+if TYPE_CHECKING:  # pragma: no cover
+    from collections.abc import Callable
 
 
 ExitException = tuple[

src/pydicom/pixels/common.py

@@ -1,7 +1,6 @@
 # Copyright 2008-2024 pydicom authors. See LICENSE file for details.
 """Common objects for pixel data handling."""
 
-from collections.abc import Callable
 from enum import Enum, unique
 from importlib import import_module
 from typing import TYPE_CHECKING, Any, TypedDict
@@ -11,6 +10,7 @@
 from pydicom.uid import UID
 
 if TYPE_CHECKING:  # pragma: no cover
+    from collections.abc import Callable
     from pydicom.dataset import Dataset
     from pydicom.pixels.decoders.base import DecodeOptions, DecodeFunction
     from pydicom.pixels.encoders.base import EncodeOptions, EncodeFunction

src/pydicom/pixels/processing.py

@@ -4,7 +4,6 @@
 from io import BytesIO
 from struct import unpack, unpack_from
 from typing import TYPE_CHECKING, cast
-from collections.abc import Iterable
 
 try:
     import numpy as np
@@ -27,6 +26,7 @@
 from pydicom.valuerep import VR
 
 if TYPE_CHECKING:  # pragma: no cover
+    from collections.abc import Iterable
     from pydicom.dataset import Dataset
 
 

src/pydicom/pixels/utils.py

@@ -5,7 +5,6 @@
 import importlib
 import logging
 from pathlib import Path
-from os import PathLike
 from struct import unpack, Struct
 from sys import byteorder
 from typing import BinaryIO, Any, cast, TYPE_CHECKING
@@ -32,6 +31,7 @@
 from pydicom.valuerep import VR
 
 if TYPE_CHECKING:  # pragma: no cover
+    from os import PathLike
     from pydicom.dataset import Dataset