Issue #19872: remove unused imports in pathlib. Patch by Vajrasky Kok.

Lib/pathlib.py

@@ -6,19 +6,12 @@ import os
 import posixpath
 import re
 import sys
-import weakref
-try:
-    import threading
-except ImportError:
-    import dummy_threading as threading
-
-from collections import Sequence, defaultdict
+from collections import Sequence
 from contextlib import contextmanager
 from errno import EINVAL, ENOENT
-from itertools import chain, count
 from operator import attrgetter
 from stat import S_ISDIR, S_ISLNK, S_ISREG, S_ISSOCK, S_ISBLK, S_ISCHR, S_ISFIFO
-from urllib.parse import quote as urlquote, quote_from_bytes as urlquote_from_bytes
+from urllib.parse import quote_from_bytes as urlquote_from_bytes
 
 
 supports_symlinks = True