Python Coding Challenge 1 : Check for Pangram
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 little lazy dog” is a pangram, because it uses the letters A-Z at least once (case is irrelevant).
Given a string, detect whether or not is is a pangram. Return True if it is, False if not. Ignore numbers and punctuations