Where is 'palindrome' defined?

[fl]

Hi,

When I search solution of reverse a string/number, I came across a short
function online:

>>> def palindrome(num):
	return str(num) == str(num)[::-1]

I thought that it is a general function. And with the following variable:

>>> a
'1234_5555'

>>> parlindrome(a)

Traceback (most recent call last):
  File "<pyshell#126>", line 1, in <module>
    parlindrome(a)
NameError: name 'parlindrome' is not defined


Then, I find that parlindrome is a special checking mirrored word.
I use Python 2.7.9. Why does the error message show   

name 'parlindrome' is not defined



Thanks,