possible bug in 0.73: verbose.level can't be "error"?

I have some kind of error in some test code and get this interesting

UserWarning: Bad val "error" on line #199
        "verbose.level : error # one of silent, error, helpful,
debug, debug-annoying"
        in file "/Users/rowen/.matplotlibrc"
        Illegal verbose string "error". Legal values are ('silent',
'helpful', 'debug', 'debug-annoying')
  warnings.warn('Bad val "%s" on line #%d\n\t"%s"\n\tin file "%s"\n\t%s'
% (val, cnt, line, fname, msg))

My .matplotlibrc worked fine with matplotlib 0.72.1 and 0.71 and "error"
was certainly an accepted value.

-- Russell