After removing my build/ and site-packages-matplotlib*, I installed the most up-to-date svn numpy and matplotlib on a RHEL4 machine. I'm getting the following errors: File "/usr/lib/python2.3/site-packages/matplotlib-0.90.1_r3867-py2.3-linux-i686.egg/matplotlib/_cm.py", line 5962, in ? cmapdat_r = revcmap(datad[cmapname]) File "/usr/lib/python2.3/site-packages/matplotlib-0.90.1_r3867-py2.3-linux-i686.egg/matplotlib/_cm.py", line 5955, in revcmap valnew = [(1.-a, b, c) for a, b, c in reversed(val)] ValueError: unpack tuple of wrong size Here is the output of all the reversed(val): (10, (1.0, 0.63529413938522339, 0.63529413938522339)) (9, (0.90000000000000002, 0.74117648601531982, 0.74117648601531982)) (8, (0.80000000000000004, 0.64705884456634521, 0.64705884456634521)) (7, (0.69999999999999996, 0.64313727617263794, 0.64313727617263794)) (6, (0.59999999999999998, 0.59607845544815063, 0.59607845544815063)) (5, (0.5, 0.74901962280273438, 0.74901962280273438)) (4, (0.40000000000000002, 0.54509806632995605, 0.54509806632995605)) (3, (0.29999999999999999, 0.3803921639919281, 0.3803921639919281)) (2, (0.20000000000000001, 0.26274511218070984, 0.26274511218070984)) (1, (0.10000000000000001, 0.30980393290519714, 0.30980393290519714)) (0, (0.0, 0.25882354378700256, 0.25882354378700256)) I don't get the error with python-2.5. reversed is defined by cbook if python doesnt have it as a builtin, but cbook yields an (index, tuple) whereas the builtin yields only the tuple. I changed cbook's reversed to agree with the python builtin, and made notes in the CHANGELOG and API_CHANGES. Darren