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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def pbkdf2_bin( data, salt, iterations=DEFAULT_PBKDF2_ITERATIONS, keylen=None, hashfunc=None ):
 """Returns a binary digest for the PBKDF2 hash algorithm of `data` with the given `salt`. It iterates `iterations` times and produces a key of `keylen` bytes. By default, SHA-256 is used as hash function; a different hashlib `hashfunc` can be provided. .. versionadded:: 0.9 :param data: the data to derive. :param salt: the salt for the derivation. :param iterations: the number of iterations. :param keylen: the length of the resulting key. If not provided the digest size will be used. :param hashfunc: the hash function to use. This can either be the string name of a known hash function or a function from the hashlib module. Defaults to sha256. """

    if not hashfunc:
        hashfunc = "sha256"

    data = to_bytes(data)
    salt = to_bytes(salt)

    if callable(hashfunc):
        _test_hash = hashfunc()
        hash_name = getattr(_test_hash, "name", None)
    else:
        hash_name = hashfunc
    return hashlib.pbkdf2_hmac(hash_name, data, salt, iterations, keylen)