def load_words(file_name):
    """ file_name (string): the name of the file containing 
        the list of words to load
    Returns: a list of valid words. Words are strings of lowercase letters
    Depending on the size of the word list, this function may take a while
    """
    print("Loading word list from file...")
    # inFile: file
    inFile = open(file_name, 'r')
    # wordlist: list of strings
    wordlist = []
    for line in inFile:
        wordlist.extend([word.lower() for word in line.split(' ')])
    print(f"   {len(wordlist)} words loaded.")
    return wordlist