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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 get_backend_class():
 """Return reference to the configured backed class."""

    # this will (intentionally) blow up if the setting does not exist
    assert hasattr(settings, 'INBOUND_EMAIL_PARSER')
    assert getattr(settings, 'INBOUND_EMAIL_PARSER') is not None

    package, klass = settings.INBOUND_EMAIL_PARSER.rsplit('.', 1)
    module = import_module(package)
    return getattr(module, klass)