jose/backends/__init__.py

try:
    from jose.backends.cryptography_backend import get_random_bytes  # noqa: F401
except ImportError:
    try:
        from jose.backends.pycrypto_backend import get_random_bytes  # noqa: F401
    except ImportError:
        from jose.backends.native import get_random_bytes  # noqa: F401

try:
    from jose.backends.cryptography_backend import CryptographyRSAKey as RSAKey  # noqa: F401
except ImportError:
    try:
        from jose.backends.pycrypto_backend import RSAKey  # noqa: F401

        # time.clock was deprecated in python 3.3 in favor of time.perf_counter
        # and removed in python 3.8. pycrypto was never updated for this. If
        # time has no clock attribute, let it use perf_counter instead to work
        # in 3.8+
        # noinspection PyUnresolvedReferences
        import time
        if not hasattr(time, "clock"):
            time.clock = time.perf_counter

    except ImportError:
        from jose.backends.rsa_backend import RSAKey  # noqa: F401

try:
    from jose.backends.cryptography_backend import CryptographyECKey as ECKey  # noqa: F401
except ImportError:
    from jose.backends.ecdsa_backend import ECDSAECKey as ECKey  # noqa: F401

try:
    from jose.backends.cryptography_backend import CryptographyAESKey as AESKey  # noqa: F401
except ImportError:
    try:
        from jose.backends.pycrypto_backend import AESKey  # noqa: F401
    except ImportError:
        AESKey = None

try:
    from jose.backends.cryptography_backend import CryptographyHMACKey as HMACKey  # noqa: F401
except ImportError:
    from jose.backends.native import HMACKey  # noqa: F401

from .base import DIRKey  # noqa: F401