Put cached_property import behind guard

Author: jacobtylerwalls

pylint/checkers/imports.py

@@ -12,7 +12,6 @@
 import sys
 from collections import defaultdict
 from collections.abc import ItemsView, Sequence
-from functools import cached_property
 from typing import TYPE_CHECKING, Any, Dict, List, Union
 
 import astroid
@@ -38,6 +37,12 @@
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
+if sys.version_info >= (3, 8):
+    from functools import cached_property
+else:
+    from astroid.decorators import cachedproperty as cached_property
+
+
 # The dictionary with Any should actually be a _ImportTree again
 # but mypy doesn't support recursive types yet
 _ImportTree = Dict[str, Union[List[Dict[str, Any]], List[str]]]