in Python:

def translate(word): """ Returns the translation of the string word into pig latin. If word is empty or contains characters other than lower case letters, return None. :param word: string :return: string or None

>>> translate("hello") "ellohay"

>>> translate("world") "orldway"

>>> translate("image") "imagehay"

>>> translate("the") "hetay"

>>> translate("")

>>> translate("Hello")

>>> translate("hello123") """