Pangram checker

You are encouraged to solve this task according to the task description, using any language you may know.
A pangram is a sentence that contains all the letters of the English alphabet at least once.

For example:   The quick brown fox jumps over the lazy dog.



Task

Write a function or method to check a sentence to see if it is a   pangram   (or not)   and show its use.



Related tasks

   determine if a string has all the same characters
   determine if a string has all unique characters


sentences = ["The quick brown fox jumps over the lazy dog.",
    "Peter Piper picked a peck of pickled peppers.",
    "Waltz job vexed quick frog nymphs."]
 
alphabet = "abcdefghijklmnopqrstuvwxyz"
 
pangram = function (toCheck)
    sentence = toCheck.lower
    fail = false
    for c in alphabet
        if sentence.indexOf(c) == null then return false
    end for
    return true
end function
 
for sentence in sentences
    if pangram(sentence) then
        print """" + sentence + """ is a Pangram"
    else 
        print """" + sentence + """ is not a Pangram"
    end if
end for