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


function pangram? {
  local alphabet=abcdefghijklmnopqrstuvwxyz
  local string="$*"
  string="${string,,}"
  while [[ -n "$string" && -n "$alphabet" ]]; do
    local ch="${string%%${string#?}}"
    string="${string#?}"
    alphabet="${alphabet/$ch}"
  done
  [[ -z "$alphabet" ]]
}