(May 16, 2021)

• Fix OMD.addlist when the added list is empty
• Add funcutils.noop, satisfying PEP 559
• Support lists for iterutils.bucketize
• Python 3.9 test fixes for OMD (PEP 584, see #271)
• Make typeutils.make_sentinel more pickleable
• jsonutils.reverse_iter_lines now works on Py3 and Windows