Python 2.6.5 (r265:79359, Mar 24 2010, 01:32:55) 
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> def square(x):
...   return x ** 2
... 
>>> square
<function square at 0x96df0>
>>> type(square)
<type 'function'>
>>> [square]
[<function square at 0x96df0>]
>>> square(11)
121
>>> def id(x):
...   return x
... 
>>> id
<function id at 0x638d70>
>>> id(4)
4
>>> id([1,1,1,1,1])
[1, 1, 1, 1, 1]
>>> def sideEffectOnly():
...   print "Thylacines are really cool."
... 
>>> sideEffectOnly()
Thylacines are really cool.
>>> def sum(m,n):
...   accum = 0
...   for i in range(m,n):
...     accum = accum + i
...   return accum
... 
>>> sum(1,101)
5050
>>> def sum2(m,n,f):
...   accum = 0
...   for i in range(m,n):
...     accum = accum + f(i)
...   return accum
... 
>>> sum2(1,5,square)