def METHOD_NAME(corpus, use_model=True, size=10):
    """Based on a corpus file prefix in "corpus" generate either word-based
    ngram (wordgram) model, or just randomly select a sentence from
    the corpus.
    Parameters
    ==========
    corpus: the prefix of the corpus file, is checked to exist
    use_model: boolean. Choose an actual sentence or generate one.
    size: The number of words to generate (only for a model).
    """
    # Get the corpus file, if not provided a full path
    if not os.path.exists(corpus):
        corpus = get_corpus(corpus)
    if use_model:
        return generate_words_markov(corpus, size=size)
    return select_sentence(corpus)