Determine if a sentence is a pangram. A pangram (Greek: παν γράμμα, pan gramma, "every letter") is a sentence using every letter of the alphabet at least once. The best known English pangram is:
The quick brown fox jumps over the lazy dog.
The alphabet used consists of ASCII letters a to z, inclusive, and is case
insensitive. Input will not contain non-ASCII symbols.
If you don't know how to run Vader tests, see: Tests.
For general information about the Vim script track, see: Help.
Wikipedia https://en.wikipedia.org/wiki/Pangram
It's possible to submit an incomplete solution so you can see how others have completed the exercise.