How to use the oscrypto._errors.pretty_message function in oscrypto

valid_hash_algorithms |= set(['raw'])

    if hash_algorithm not in valid_hash_algorithms:
        valid_hash_algorithms_error = '"md5", "sha1", "sha224", "sha256", "sha384", "sha512"'
        if certificate_or_public_key.algorithm == 'rsa' and not rsa_pss_padding:
            valid_hash_algorithms_error += ', "raw"'
        raise ValueError(pretty_message(
            '''
            hash_algorithm must be one of %s, not %s
            ''',
            valid_hash_algorithms_error,
            repr(hash_algorithm)
        ))

    if certificate_or_public_key.algorithm != 'rsa' and rsa_pss_padding:
        raise ValueError(pretty_message(
            '''
            PSS padding can only be used with RSA keys - the key provided is a
            %s key
            ''',
            certificate_or_public_key.algorithm.upper()
        ))

    if certificate_or_public_key.algorithm == 'rsa' and hash_algorithm == 'raw':
        if len(data) > certificate_or_public_key.byte_size - 11:
            raise ValueError(pretty_message(
                '''
                data must be 11 bytes shorter than the key size when
                hash_algorithm is "raw" - key size is %s bytes, but data is
                %s bytes long
                ''',
                certificate_or_public_key.byte_size,

raise TypeError(pretty_message(
            '''
            data must be a byte string, not %s
            ''',
            type_name(data)
        ))

    valid_hash_algorithms = set(['md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512'])
    if certificate_or_public_key.algorithm == 'rsa' and not rsa_pss_padding:
        valid_hash_algorithms |= set(['raw'])

    if hash_algorithm not in valid_hash_algorithms:
        valid_hash_algorithms_error = '"md5", "sha1", "sha224", "sha256", "sha384", "sha512"'
        if certificate_or_public_key.algorithm == 'rsa' and not rsa_pss_padding:
            valid_hash_algorithms_error += ', "raw"'
        raise ValueError(pretty_message(
            '''
            hash_algorithm must be one of %s, not %s
            ''',
            valid_hash_algorithms_error,
            repr(hash_algorithm)
        ))

    if certificate_or_public_key.algorithm != 'rsa' and rsa_pss_padding:
        raise ValueError(pretty_message(
            '''
            PSS padding can only be used with RSA keys - the key provided is a
            %s key
            ''',
            certificate_or_public_key.algorithm.upper()
        ))

''',
            repr(hash_algorithm)
        ))

    hash_func = getattr(hashlib, hash_algorithm)

    # The maximal bit size of a non-negative integer is one less than the bit
    # size of the key since the first bit is used to store sign
    em_bits = key_length - 1
    em_len = int(math.ceil(em_bits / 8))

    message_digest = hash_func(message).digest()
    hash_length = len(message_digest)

    if em_len < hash_length + salt_length + 2:
        raise ValueError(pretty_message(
            '''
            Key is not long enough to use with specified hash_algorithm and
            salt_length
            '''
        ))

    if salt_length > 0:
        salt = os.urandom(salt_length)
    else:
        salt = b''

    m_prime = (b'\x00' * 8) + message_digest + salt

    m_prime_digest = hash_func(m_prime).digest()

    padding = b'\x00' * (em_len - salt_length - hash_length - 2)

:param salt_length:
        The length of the salt as an integer - typically the same as the length
        of the output from the hash_algorithm

    :param key_length:
        The length of the RSA key, in bits

    :param message:
        A byte string of the message to pad

    :return:
        The encoded (passed) message
    """

    if _backend != 'winlegacy' and sys.platform != 'darwin':
        raise SystemError(pretty_message(
            '''
            Pure-python RSA PSS signature padding addition code is only for
            Windows XP/2003 and OS X
            '''
        ))

    if not isinstance(message, byte_cls):
        raise TypeError(pretty_message(
            '''
            message must be a byte string, not %s
            ''',
            type_name(message)
        ))

    if not isinstance(salt_length, int_types):
        raise TypeError(pretty_message(

OSError - when an error is returned by OpenSSL

    :return:
        A byte string of the plaintext
    """

    if not isinstance(key, byte_cls):
        raise TypeError(pretty_message(
            '''
            key must be a byte string, not %s
            ''',
            type_name(key)
        ))

    if not isinstance(data, byte_cls):
        raise TypeError(pretty_message(
            '''
            data must be a byte string, not %s
            ''',
            type_name(data)
        ))

    if cipher != 'rc4' and not isinstance(iv, byte_cls):
        raise TypeError(pretty_message(
            '''
            iv must be a byte string, not %s
            ''',
            type_name(iv)
        ))

    if cipher != 'rc4' and padding is None:
        raise ValueError('padding must be specified')

:return:
        A Certificate object
    """

    if isinstance(source, Asn1Certificate):
        certificate = source

    elif isinstance(source, byte_cls):
        certificate = parse_certificate(source)

    elif isinstance(source, str_cls):
        with open(source, 'rb') as f:
            certificate = parse_certificate(f.read())

    else:
        raise TypeError(pretty_message(
            '''
            source must be a byte string, unicode string or
            asn1crypto.x509.Certificate object, not %s
            ''',
            type_name(source)
        ))

    return _load_x509(certificate)

:return:
        A PublicKey object
    """

    if isinstance(source, PublicKeyInfo):
        public_key = source

    elif isinstance(source, byte_cls):
        public_key = parse_public(source)

    elif isinstance(source, str_cls):
        with open(source, 'rb') as f:
            public_key = parse_public(f.read())

    else:
        raise TypeError(pretty_message(
            '''
            source must be a byte string, unicode string or
            asn1crypto.keys.PublicKeyInfo object, not %s
            ''',
            type_name(source)
        ))

    return _load_key(public_key)

''',
            repr(algorithm)
        ))

    if algorithm == 'rsa':
        if bit_size not in set([1024, 2048, 3072, 4096]):
            raise ValueError(pretty_message(
                '''
                bit_size must be one of 1024, 2048, 3072, 4096, not %s
                ''',
                repr(bit_size)
            ))

    elif algorithm == 'dsa':
        if bit_size not in set([1024]):
            raise ValueError(pretty_message(
                '''
                bit_size must be 1024, not %s
                ''',
                repr(bit_size)
            ))

    elif algorithm == 'ec':
        if curve not in set(['secp256r1', 'secp384r1', 'secp521r1']):
            raise ValueError(pretty_message(
                '''
                curve must be one of "secp256r1", "secp384r1", "secp521r1", not %s
                ''',
                repr(curve)
            ))

    cf_dict = None

has_asn1 = hasattr(certificate_or_public_key, 'asn1')
    valid_types = (PublicKeyInfo, Certificate)
    if not has_asn1 or not isinstance(certificate_or_public_key.asn1, valid_types):
        raise TypeError(pretty_message(
            '''
            certificate_or_public_key must be an instance of the
            oscrypto.asymmetric.PublicKey or oscrypto.asymmetric.Certificate
            classes, not %s
            ''',
            type_name(certificate_or_public_key)
        ))

    algo = certificate_or_public_key.asn1['algorithm']['algorithm'].native
    if algo != 'rsa':
        raise ValueError(pretty_message(
            '''
            certificate_or_public_key must be an RSA key, not %s
            ''',
            algo.upper()
        ))

    if not isinstance(data, byte_cls):
        raise TypeError(pretty_message(
            '''
            data must be a byte string, not %s
            ''',
            type_name(data)
        ))

    rsa_public_key = certificate_or_public_key.asn1['public_key'].parsed
    transformed_int = pow(

:return:
        A tuple of two byte strings (iv, ciphertext)
    """

    if len(key) < 5 or len(key) > 16:
        raise ValueError(pretty_message(
            '''
            key must be 5 to 16 bytes (40 to 128 bits) long - is %s
            ''',
            len(key)
        ))

    if not iv:
        iv = rand_bytes(8)
    elif len(iv) != 8:
        raise ValueError(pretty_message(
            '''
            iv must be 8 bytes long - is %s
            ''',
            len(iv)
        ))

    return (iv, _encrypt('rc2', key, data, iv, True))