def gnext():
  '''
  >>> gnext()
  pochi
  >>> gnext()
  tama
  >>> gnext()
  mike
  >>> gnext()
  nameless
  '''
  try:
    print f.next()
  except StopIteration:
    print 'nameless'

f = iter(['pochi', 'tama', 'mike'])
gnext()
gnext()
gnext()
gnext()

import doctest
doctest.testmod()

pochi
tama
mike
nameless
**********************************************************************
File "t.py", line 3, in __main__.gnext
Failed example:
    gnext()
Expected:
    pochi
Got:
    nameless
**********************************************************************
File "t.py", line 5, in __main__.gnext
Failed example:
    gnext()
Expected:
    tama
Got:
    nameless
**********************************************************************
File "t.py", line 7, in __main__.gnext
Failed example:
    gnext()
Expected:
    mike
Got:
    nameless
**********************************************************************
1 items had failures:
   3 of   4 in __main__.gnext
***Test Failed*** 3 failures.