Determine if a string is a panagram with python

A pangram is a sentence that contains every single letter of the alphabet at least once. For example, the sentence «The quick brown fox jumps over the lazy dog» is a pangram, because it uses the letters A-Z at least once (case is irrelevant).

I’ve designed this code snippet to find out if a given string «s» is a panagram or not.

#!/usr/bin/python
# miguel.ortiz
import string

s='The quick brown fox jumps over the lazy dog'
def is_pangram(s):
    p = [ w for w in string.ascii_lowercase if w not in s.lower() ]
    if not p :
        return True
    else :
        return False
is_panagram(s)