In the most concise way possible (also with the least iterations), given any sentence, determine if the sentence contains all the letters of the alphabet. Do so by creating a method called contains_all? that accepts a string as a parameter and returns true or false based upon the result.
sentence_1 = "Sam is the man and has a very big plan to dominate coding"
sentence_2 = "The quick brown fox jumps over the lazy dog"
sentence_3 = "Look over the wall and you will see every 1 persons dog alive"