[Checkins] [zopefoundation/ZODB] 082af7: Use weakref.WeakSet rather than transaction.weakse...

[Julien Muchembled]

  Branch: refs/heads/weakset
  Home:   https://github.com/zopefoundation/ZODB
  Commit: 082af72c2434e00a5e80e9ccde621ba87deb1461
      https://github.com/zopefoundation/ZODB/commit/082af72c2434e00a5e80e9ccde621ba87deb1461
  Author: Julien Muchembled <jm at nexedi.com>
  Date:   2019-09-17 (Tue, 17 Sep 2019)

  Changed paths:
    M src/ZODB/DB.py

  Log Message:
  -----------
  Use weakref.WeakSet rather than transaction.weakset.WeakSet