def get_grams(sentence, n):
    """
    Returns phrases i.e. windowed sub
    strings with range (1-N) window
    Keyword arguments:
    sentence -- utterance  (str)
    n -- max_ngram (int)
    """
    all_grams = []
    for l in range(1, n + 1):
        grams = [" ".join(sentence[i:i + l]) for i in range(len(sentence) - l + 1)]
        all_grams = all_grams + grams
    return all_grams