def uses_only(word, String_of_letters):
    for letter in word:
        if letter not in String_of_letters:
            return False
    return True

383777546aed9a1f91c55058b490a7fb764d0fe6
<mask token>

def uses_only(word, String_of_letters):
    for letter in word:
        if letter not in String_of_letters:
            return False
    return True
