pangram.rb

module Pangram do
  def self.is?(string)
    string
      .downcase
      .split("")
      .select { |character| in_alphabet? character }
      .uniq
      .sort == alphabet
  end
  
  def alphabet
    ('a'..'z').to_a
  end
  
  def in_alphabet character
    alphabet.include? character
  end
end

# Usage:
# Pangram.is("hey hey abcDEfg ihjklmonpqrstuvqxyz you you")
# => true