def METHOD_NAME(key, nonce=None):
    """Create a new Salsa20 cipher
    :keyword key: The secret key to use. It must be 16 or 32 bytes long.
    :type key: bytes/bytearray/memoryview
    :keyword nonce:
        A value that must never be reused for any other encryption
        done with this key. It must be 8 bytes long.
        If not provided, a random byte string will be generated (you can read
        it back via the ``nonce`` attribute of the returned object).
    :type nonce: bytes/bytearray/memoryview
    :Return: a :class:`Crypto.Cipher.Salsa20.Salsa20Cipher` object
    """
    if nonce is None:
        nonce = get_random_bytes(8)
    return Salsa20Cipher(key, nonce)