First solution in Clear category for Pangram by
alnum = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
used = 
for ch in text.upper():
if (ch in alnum) and (ch not in used): used.append(ch)
if __name__ == '__main__':
# These "asserts" using only for self-checking and not necessary for auto-testing
assert check_pangram("The quick brown fox jumps over the lazy dog."), "brown fox"
assert not check_pangram("ABCDEF"), "ABC"
assert check_pangram("Bored? Craving a pub quiz fix? Why, just come to the Royal Oak!"), "Bored?"
Dec. 1, 2016