Python 3 preparation: "raise" syntax. Changing "raise Exception, value" to "raise Exception(value)". Tool-assisted patch. Particular cases to check carefully are the one place in frontends/ZRoundup/ZRoundup.py where a string exception needed to be fixed, and the one in roundup/cgi/client.py involving raising an exception with a traceback (requires three-argument form of raise in Python 2, which as I understand it requires exec() to avoid a Python 3 syntax error).

--- a/test/test_locking.py	Tue Jul 24 21:36:02 2018 +0000
+++ b/test/test_locking.py	Tue Jul 24 21:39:58 2018 +0000
@@ -36,7 +36,7 @@
         except:
             pass
         else:
-            raise AssertionError, 'no exception'
+            raise AssertionError('no exception')
         release_lock(f)
         f = acquire_lock(self.path)
         release_lock(f)