def stanza_lengths(tokenized_poem):
    """
    Returns a comma-delimited string of stanza lengths
    """

    stanzas = []

    i = 0
    for line in tokenized_poem:
        if line != ['']:
            i += 1
        else:
            stanzas.append(str(i))
            i = 0
    if i != 0:
        stanzas.append(str(i))

    joined = ','.join(stanzas)

    return joined