HASKELL ONLY

Design a pangram function in Haskell which takes a string as input, and returns true if the string is a pangram, and false otherwise.

Pangrams are strings that contain every letter of the english alphabet at least once.They are not case sensitive,so a letter may appear in either upper case, lower case, or both.

Example of what it may look like:

>pangram "Pack my box with five dozen liquor jugs!!"

True // what is returned

> pangram "The cat is not white"

False //what is returned