Python 3.2.1 (v3.2.1:ac1f7e5c0510, Jul  9 2011, 01:03:53) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
Python 3.2.1 (v3.2.1:ac1f7e5c0510, Jul  9 2011, 01:03:53) 
Type "copyright", "credits" or "license" for more information.

IPython 0.11 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: from time import sleep

In [2]: def sleep2(time):
   ...:     def sleep3():
   ...:         sleep(time)
   ...:         return time
   ...:     return sleep3
   ...: 

In [3]: sleep2(2)
Out[3]: <function __main__.sleep3>

In [4]: sleep2(2)()
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
/Users/maarten/.pystartup in <module>()
----> 1 sleep2(2)()

/Users/maarten/.pystartup in sleep3()
      1 def sleep2(time):
      2     def sleep3():
----> 3         sleep(time)
      4         return time
      5     return sleep3

NameError: global name 'sleep' is not defined

In [5]: [sleep2(i) for i in range(1,5)]
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
/Users/maarten/.pystartup in <module>()
----> 1 [sleep2(i) for i in range(1,5)]

/Users/maarten/.pystartup in <listcomp>(.0)
----> 1 [sleep2(i) for i in range(1,5)]

NameError: global name 'sleep2' is not defined

In [6]: