import cgitb
import inspect
import sys

def badfunc(x):
    del x  # This is the bad part
    raise ValueError('fail')

try:
    badfunc(1)
except:
    cgitb.handler()

print 72*'*'
print 'Above, you should have seen a pretty traceback, but you saw a fallback.'
print ''
print "Here's why"
print 72*'*'

try:
    badfunc(1)
except:
    ei = sys.exc_info()
    for frame in inspect.getinnerframes(ei[2]):
        print 'Will formatargvalues on %r' % (frame,)
        print inspect.formatargvalues(*inspect.getargvalues(frame[0]))
        print ''