how is the readline set_completer function suppose to work

[sinbad.sinbad at gmail.com]

Below i was expecting the test() function to be called, but it doesn't. Am i doing it wrong?
By the way i'm running version 2.7.10 on a mac.

$python

>>> import readline
>>> def test():
...   print("test")
...
>>> test()
test
>>> print(help(readline))

None
>>> readline.set_completer(test)
>>> raw_input()

'\t\t\t'
>>>