def label(length=None):

   first = random.choice(alpha)
   rest = [random.choice(alphaDigit) for i in xrange(length or 7)]
   newLabel = first + ''.join(rest)
   return newLabel
Can be redefined to generate post event after excution is done
dataset/ETHPy150Open twisted/nevow/examples/image_uploader/imagination.py/label--crossover with--dataset/ETHPy150Open ipython/ipython-py3k/IPython/deathrow/gui/wx/ipshell_nonblocking.py/NonBlockingIPShell._after_execute