convert a string into sha1hash. For json object/array, first convert
        it into canonical json string.

def any2sha1(text):
    """
        convert a string into sha1hash. For json object/array, first convert
        it into canonical json string.
    """
    # canonicalize json object or json array
    if type(text) in [dict, list]:
        text = json.dumps(text, sort_keys=True)

    # assert question as utf8
    if isinstance(text, unicode):
        text = text.encode('utf-8')

    return hashlib.sha1(text).hexdigest()